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
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