Question

Use a substitution strategy to solve the following problem.

Answer 1

Answer:

The length of the equal sides of the isosceles triangle with a perimeter of 34 cm perimeter is 12 cm

The length of the equal sides of the isosceles triangle with a perimeter of 82 cm perimeter is 36 cm

The base length of both triangles is 10 cm

Step-by-step explanation:

The given parameters are;

The base length of the triangles are equal

The base length of one of the triangle = The base length of the other triangle

The equal sides of one of the triangles = 3 × The length of the equal sides of the other

The perimeter of the triangles are; 34 cm and 82 cm

Let 'b' represent the base length of each triangle, let 'a' represent the length of an equal side of the smaller triangle with a perimeter of 34 cm and let 'c' represent the length of an equal side of the larger triangle with a perimeter of 82 cm

For the smaller triangle, we have;

b + 2·a = 34..(1)

For the other triangle;

b + 2·c = 82...(2)

Given that the side length of the larger triangle are larger than those of the smaller triangle, and that the side length of the larger triangle is 3 times the side length of the smaller triangle, we get;

c = 3·a

By the substitution method, from equation (2) we get;

b + 2·c = b + 2 × 3·a = b + 6·a = 82

∴ b + 6·a = 82...(3)

Subtracting equation (1) from equation (3) gives;

b + 6·a - (b + 2·a) = 82 - 34 = 48

b - b + 6·a - 2·a = 48

4·a = 48

a = 48/4 = 12

The length of the equal sides of the 34 cm perimeter (smaller) isosceles triangle, a = 12 cm

From c = 3·a, and a = 12, we get;

c = 3 × 12 = 36

The length of the equal sides of the 82 cm perimeter (larger) isosceles triangle, c = 36 cm

From equation (1), we get;

b + 2·a = 34

∴ b + 2 × 12 = 34

b = 34 - 2 × 12 = 10

The base length of both triangles, b = 10 cm