Find the slope of each Altitude:
D(2,4) E(-3,-6) F(4,7)

What are the sotions to the quadratic equation 9x^2=4

Evaluate cos2θ for cosθ = square root of 3/2

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?