Step 1: Theorem
In geometry, an isosceles triangle is a triangle that has two sides of equal length.
Step 2: Given data
Two sides are given with lengths 5 and 9.
Step 3:
The two equal lengths can be 5 and 5 or 9 and 9
Step 4:
The third length can be 5 or 9.
Final answer
is either 5 or 9.
