Answer:
x = [tex]\sqrt{30}[/tex]
Step-by-step explanation:
Applying altitude- on - hypotenuse theorem.
(leg of large Δ )² = ( part of hypotenuse below it ) × ( whole hypotenuse )
x² = 3 × (3 + 7) = 3 × 10 = 30 ( take square root of both sides )
x = [tex]\sqrt{30}[/tex]