Solve quadratic inequality x^2+4x≥0

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?

Look at the example below which shows how the product property of radicals is used to simplify a radical. use the product property of radicals to simplify the following radical.

Right triangle abc has three sides with lengths ab= 119, bc = 169, ca= 120. find the value of cos c. hint: draw and label the triangle. the hypotenuse is always the longest.