Quadrilaterals - Basic Geometry

Card 0 of 20

Question

Two rectangles are similar. One rectangle has dimensions centimeters and 100 centimeters; the other has dimensions 400 centimeters and centimeters.

What value of makes this a true statement?

Answer

For polygons to be similar, side lengths must be in proportion.

Case 1:

and 100 in the first rectangle correspond to and 400 in the second, respectively.

The resulting proportion would be:

This is impossible since must be a positive side length.

Case 2:

and 100 in the first rectangle correspond to 400 and in the second, respectively.

The correct proportion statement must be:

Cross multiply to solve for :

200 cm is the only possible solution.

Compare your answer with the correct one above

Question

Rectangles

Note: figure not drawn to scale.

Examine the above figure.

What is ?

Answer

By similarity, we can set up the proportion:

Substitute:

Compare your answer with the correct one above

Question

Which of the following is not a necessary condition for rectangles A and B to be similar?

Answer

All sides being equal is a condition for congruency, not similarity. Similarity focuses on the ratio between rectangles and not on the equivalency of all sides. As for the statement regarding the equal angles, all rectangles regardless of similarity or congruency have four 90 degree angles.

Compare your answer with the correct one above

Question

What value of makes the two rectangles similar?

25

Answer

For two rectangles to be similar, their sides have to be proportional (form equal ratios). The ratio of the two longer sides should equal the ratio of the two shorter sides.

However, the left ratio in our proportion reduces.

We can then solve by cross multiplying.

We then solve by dividing.

Compare your answer with the correct one above

Question

The following images are not to scale.

In order to make these two rectangles similar, what must the width of rectangle on the right be?

Similar_rectangles

Answer

For two rectangles to be similar, their sides must be in the same ratio.

This problem can be solved using ratios and cross multiplication.

Let's denote the unknown width of the right rectangle as x.

Compare your answer with the correct one above

Question

Two rectangles are similar. One has an area of and the other an area of . If the first has a base length of , what is the height of the second rectangle?

Answer

The goal is to solve for the height of the second rectangle.

Similar rectangles function on proportionality - that is, the ratios of the sides between two rectangles will be the same. In order to determine the height, we will be using this concept of ratios through solving for variables from the area.

First, it's helpful to achieve full dimensions for the first rectangle.

It is given that its base length is 5, and it has an area of 20.


This means the first rectangle has the dimensions 5x4.

Now, we may utilize the concept of ratios for similarity. The side lengths of the first rectangle is 5x4, so the second recatangle must have sides that are proportional to the first's.

We have the information for the first rectangle, so the data may be substituted in.

is the ratio factor that will be used to solve for the height of the second rectangle. This may be substituted into the area formula for the second rectangle.

Therefore, the height of the second rectangle is 10.

Compare your answer with the correct one above

Question

There are two rectangles. One has a perimeter of and the second one has a perimeter of . The first rectangle has a height of . If the two rectangles are similiar, what is the base of the second rectangle?

Answer

The goal of this problem is to figure out what base length of the second rectangle will make it similar to the first rectangle.

Similar rectangles function on proportionality - that is, the ratios of the sides between two rectangles will be the same. In order to determine the base, we will be using this concept of ratios through solving for variables from the perimeter.

First, all the dimensions of the first rectangle must be calculated.

This can be accomplished through using the perimeter equation:

This means the dimensions of the first rectangle are 10x5. We will use this information for the ratios to calculate dimensions that would yield the second rectangle similar because of proprotions.

is the ratio factor we will use to solve for the base of the second rectangle.

This will require revisiting the perimeter equation for the second rectangle.

Compare your answer with the correct one above

Question

The attached image represents the dimensions of two different brands of manufactured linoleum tile. If the two tiles are similar, what would be the length of the large tile, given the information in the figure below?

Varsity record

Answer

Two rectangles are similar if their length and width form the same ratio. The small tile has a width of and a width of , providing us with the following ratio:

Since the length of similar triangles is twice their respective width, the length of the large tile can be determined as such:

Compare your answer with the correct one above

Question

Are these rectangles similar?

Similar or no 1

Answer

To determine if these rectangles are similar, set up a proportion:

This proportion compares the ratio between the long sides in each rectangle to the ratio of the short sides in each rectangle. If they are the same, cross-multiplying will produce a true statement, and the rectangles are similar:

These rectangles aren't similar.

Compare your answer with the correct one above

Question

Are these rectangles similar?

Similar or no 2

Answer

To determine if the rectangles are similar, set up a proportion comparing the short sides and the long sides from each rectangle:

cross-multiply

since that's true, the rectangles are similar.

To find the scale factor, either divide 25 by 10 or 7.5 by 3. Either way you will get 2.5.

Compare your answer with the correct one above

Question

Rectangles 1

Figure NOT drawn to scale

Refer to the above figure.

True or false: Rectangle Rectangle .

Answer

Two rectangles are similar if and only if their sides are in proportion. Specifically,

Rectangle Rectangle

if

Since is located at the point , it follows that and . Since is located at the point , it follows that and . Substituting in the aforementioned proportion statement, we get

.

Reducing to lowest terms, this is

.

This is false, so Rectangle Rectangle .

Compare your answer with the correct one above

Question

Congruent rectangle

Consider the similar rectangles and shown here. The lengths of the following sides are given:

What is the length of the side ?

Answer

Comparing the sides and , we see that is the length of , as shown here:

.

Since these two rectangles are similar, all pairs of corresponding sides are similar. Hence, the ratio of to is also , and we can calculate the length of by setting up and solving a proportion:

.

Hence, the length of the side is units.

Compare your answer with the correct one above

Question

Screen_shot_2013-09-16_at_11.28.29_am

What is the area of the rectangle in the diagram?

Answer

The area of a rectangle is found by multiplying the length by the width.

The length is 12 cm and the width is 7 cm.

Therefore the area is 84 cm2.

Compare your answer with the correct one above

Question

A rectangle has a perimeter of . The length is ten meters more than the width. What is the area of the rectangle?

Answer

Given a rectangle, the general equation for the perimeter is and area is where is the length and is the width.

Let = width and = length

So the equation to solve becomes so thus the width is and the length is .

Thus the area is

Compare your answer with the correct one above

Question

Which of the following information would not be sufficient to find the area of a rectangle?

Answer

The area of a rectangle can be calculated by multiplying the lengths of two adjacent sides. All of the choices given lists sufficient information, with one exception. We examine each of the choices.

The lengths of one pair of adjacent sides: This choice is false, as is directly stated above.

The perimeter and the length of one side: Using the perimeter formula, you can find the length of an adjacent side, making this choice false.

The lengths of one side and a diagonal: using the Pythagorean Theorem, you can find the length of an adjacent side, making this choice false.

The lengths of one pair of opposite sides: this gives you no way of knowing the lengths of the adjacent sides. This is the correct choice.

Compare your answer with the correct one above

Question

Figure3

Find the area of the polygon.

Answer

Drawing a vertical line at the end of the side of length divides the shape into a rectangle and a right triangle.

Figure5

The sum of the areas of the two shapes is the area of the polygon. Multiply the length of the rectangle by its width to find the area of the rectangle, and use the formula , where is the base and is the height of the triangle, to find the area of the triangle. Adding them together gives the answer.

Compare your answer with the correct one above

Question

One side of a rectangle is 7 inches and another is 9 inches. What is the area of the rectangle in inches?

Answer

To find the area of a rectangle, multiply its width by its height. If we know two sides of the rectangle that are different lengths, then we have both the height and the width.

Compare your answer with the correct one above

Question

What is the area of a rectangle whose length and width is inches and inches, respectively?

Answer

The area of any rectangle with length, and width, is:

Compare your answer with the correct one above

Question

What is the area of a rectangle that has a length of and a width of ?

Answer

Recall how to find the area of a rectangle:

Now, plug in the given length and width to find the area.

Compare your answer with the correct one above

Question

What is the area of a rectangle that has a length of and a width of ?

Answer

Recall how to find the area of a rectangle:

Now, plug in the given length and width to find the area.

Compare your answer with the correct one above

Tap the card to reveal the answer