Answer:
x = 8
Explanation:
Since the triangle is isosceles then the segment from the vertex is a perpendicular bisector, dividing the triangle into 2 right triangles.
Using Pythagoras' identity on the right triangle on the left
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
(
x )² + 8² = (
)²
x² + 64 = 80 ( subtract 64 from both sides )
x² = 16 ( multiply both sides by 4 )
x² = 64 ( take the square root of both sides )
x =
= 8 ← positive value only required