Given sides a, b, and c, finding the perimeter of a triangle is given by the following formula:
Start with a scalene triangle and label the sides as shown below.
Triangle with sides a, b, and c
P = a + b + c
Find the perimeter of a triangle when a = 3 cm, b = 5 cm, and c = 7
P = 3 + 5 + 7 = 15 cm
If P = 30 cm and a = 5 and b = 7, what is c?
Using the formula P = a + b + c, replace everything you know or everything given to you into the formula
Things that are given are P = 30, a = 8, and b = 10
Replacing them into the formula gives:
30 = 8 + 10 + c
30 = 18 + c
You end up with an addition equation that you can solve to get c
However, some mental math should provide you with an answer too.
Replace c by a question mark (?) and say to yourself the following:
18 + ? = 30 or what can I add to 18 to get 30 ? 18 + 12 = 30, so c = 12
If P = 20 cm, b = 7 and c = 8, what is a?
Using the formula P = a + b + c, replace everything you know or everything given to you into the formula
Things that are given are P = 20, b = 7, and c = 8
Replacing them into the formula gives:
20 = a + 7 + 8
20 = a + 15
What can I add to 15 to get 20? The answer is 5, so a = 5
This article was originally published on The basic-mathematics. Read the original article.
Source:
https://www.basic-mathematics.com/perimeter-of-a-triangle.html
Start with a scalene triangle and label the sides as shown below.
Triangle with sides a, b, and c
P = a + b + c
Find the perimeter of a triangle when a = 3 cm, b = 5 cm, and c = 7
P = 3 + 5 + 7 = 15 cm
If P = 30 cm and a = 5 and b = 7, what is c?
Using the formula P = a + b + c, replace everything you know or everything given to you into the formula
Things that are given are P = 30, a = 8, and b = 10
Replacing them into the formula gives:
30 = 8 + 10 + c
30 = 18 + c
You end up with an addition equation that you can solve to get c
However, some mental math should provide you with an answer too.
Replace c by a question mark (?) and say to yourself the following:
18 + ? = 30 or what can I add to 18 to get 30 ? 18 + 12 = 30, so c = 12
If P = 20 cm, b = 7 and c = 8, what is a?
Using the formula P = a + b + c, replace everything you know or everything given to you into the formula
Things that are given are P = 20, b = 7, and c = 8
Replacing them into the formula gives:
20 = a + 7 + 8
20 = a + 15
What can I add to 15 to get 20? The answer is 5, so a = 5
This article was originally published on The basic-mathematics. Read the original article.
Source:
https://www.basic-mathematics.com/perimeter-of-a-triangle.html
