Question

What is the value of x?

A. 2 Units
B. 3 Units
C. 5 Units
D. 8 Units

Answer 1

You need the formula for geometric mean for right triangles as it applies to the altitude. For us, that formula will be
`(BD)/(AD)=(CD)/(BD)` where BD is your altitude. The formula then, filled in accordingly, would be
`(10)/(x)=(4x)/(10)`. We cross multiply to get that
`4x^2=100`. Divide both sides by 4 to get
`x^2=25`, so x = 5. Choice C is the one you want.