Answer:
12.0 cm
Explanation:
✔️First, find the height, BC, of the trapezium using Pythagorean Theorem.
BC² = 10² - (9 -3)²
BC² = 10² - 6²
BC² = 64
BC = √64
BC = 8 cm
✔️Find AC using Pythagorean Theorem:
AC² = AB² + BC²
AC² = 9² + 8²
AC² = 145
AC = √145
AC = 12.0415946 ≈ 12.0 (3 significant figures)