Answer:
6.5 cm
Step-by-step explanation:
You want the side lengths in an isosceles triangle with a perimeter of 20 cm and a base of 7 cm.
Sides
The perimeter is the sum of the side lengths. The two sides of an isosceles triangle are the same length. If that length is represented by s, then we have ...
p = 2s + b . . . . . . perimeter is the sum of the sides
20 = 2s + 7 . . . . using given values
13 = 2s . . . . . . . subtract 7
13/2 = 6.5 = s . . . divide by 2
The side length is 6.5 cm.
