What is the value of x?

x = 15

Step-by-step explanation:

Using the Altitude on Hypotenuse theorem

( leg of large Δ )² = (part of hypotenuse below it ) × ( whole hypotenuse )

Thus

x² = 9 × (9 + 16) = 9 × 25 = 225 ( take the square root of both sides )

x = = 15

In return for fifteen million dollars, or approximately eighteen dollars per square mile, the United States nominally acquired a total of 828,000 sq mi (2,140,000 km2; 530,000,000 acres).