Answer:
17"
Step-by-step explanation:
Isosceles means there are two equal sides in this triangle.
So the height not only is perpendicular to the base, but also cuts the base in half.
Each half is 15 inches. (30÷2=15) See image.
These half triangles formed by the height, are right triangles. You can use Pythagorean theorem or if you're familiar with the pythagorean triple 8, 15, 17, you will find the length of the side is 17 inches. See image.
