ACT Math : How to find the perimeter of an acute / obtuse triangle
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Example Questions
Example Question #1 : How To Find The Perimeter Of An Acute / Obtuse Triangle
Two similiar triangles have a ratio of perimeters of 
If the smaller triangle has sides of 3, 7, and 5, what is the perimeter of the larger triangle.
Adding the sides gives a perimeter of 15 for the smaller triangle. Multipying by the given ratio of 
Example Question #2 : How To Find The Perimeter Of An Acute / Obtuse Triangle
Two similiar triangles exist where the ratio of perimeters is 4:5 for the smaller to the larger triangle. If the larger triangle has sides of 6, 7, and 12 inches, what is the perimeter, in inches, of the smaller triangle?
18
25
23
20
20
The larger triangle has a perimeter of 25 inches. Therefore, using a 4:5 ratio, the smaller triangle's perimeter will be 20 inches.
Example Question #171 : Act Math
Two similar triangles' perimeters are in a ratio of 
1. Find the perimeter of the larger triangle:
2. Use the given ratio to find the perimeter of the smaller triangle:
Cross multiply and solve:
Example Question #2 : Acute / Obtuse Triangles
There are two similar triangles. Their perimeters are in a ratio of 
Use proportions to solve for the perimeter of the larger triangle:
Cross multiply and solve:
Example Question #1 : How To Find The Perimeter Of An Acute / Obtuse Triangle
Two similar triangles have perimeteres in the ratio 
Since the perimeter of the smaller triangle is 
In cross multiplying this identity, we get 
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