Answer:
The perimeter is 7b
Step-by-step explanation:
An isosceles triangle has exactly two sides of the same length. Suppose we have an isosceles triangle with the base as the unequal side length of b.
The perimeter of the triangle is:
P = x + x + b = 2x + b
Being x the two equal side lengths.
It's given the base b of the triangle is one-third of any of the other sides, that is:
b = 1/3 x
Or, equivalently:
x = 3b
Thus, the perimeter of the triangle is:
P = 2x + b = = 2(3b) + b
P = 6b + b = 7b
The perimeter is 7b
