Armando is marking off a grass field for soccer game, he has a long tape measure and chalk for lining the field. Armando wants to be sure that the corners of the field are the right angles. how can he use the tape measure to ensure that he makes right angles?

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

the expected value of the random variable : 0, 1 and 2

step-by-step explanation:

the answer will be b x² +x-1

step-by-step explanation: