How to find the perimeter of a pentagon - ACT Math
Card 0 of 3
One side of a regular pentagon is 
. Find the perimeter of the pentagon.
One side of a regular pentagon is
In a regular pentagon, all of the sides are the same length.
The perimeter can then be found by summing all 
sides or multiplying 
by 
.
In a regular pentagon, all of the sides are the same length.
The perimeter can then be found by summing all
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What is the perimeter of the regular pentagon pictured above?
What is the perimeter of the regular pentagon pictured above?
The key word in this question is "regular." Since the pentagon is regular, all of its sides are equal. This means that it, in fact, looks like:
The perimeter for this is simply 
or 
.
The key word in this question is "regular." Since the pentagon is regular, all of its sides are equal. This means that it, in fact, looks like:
The perimeter for this is simply
Compare your answer with the correct one above
A regular pentagon has a side length of 
. Find its perimeter.
A regular pentagon has a side length of
Because we're told the pentagon is a regular polygon, this means that all of its sides are the same length. That is, the side lengths are congruent.
In order to solve for the perimeter, which is the sum of all sides, we can use a multiplication shortcut of:
, where 
is perimeter, 
is length of the sides, and 
is the number of sides of the polygon.
Using the information given in the problem, the values can be substituted in.
Note that this math is the same as adding 
five times:
Because we're told the pentagon is a regular polygon, this means that all of its sides are the same length. That is, the side lengths are congruent.
In order to solve for the perimeter, which is the sum of all sides, we can use a multiplication shortcut of:
Using the information given in the problem, the values can be substituted in.
Note that this math is the same as adding
Compare your answer with the correct one above