Tony purchased a prepaid phone card for $20.00. Calls cost 9 cents a minute using this card. The credit, C (in dollars), left on the card after it is used for x minutes of calls is given by the following function. =Cx−20.000.09x How much credit is left on the card after Tony uses it for 15 minutes of calls?

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)

answer: 7

step-by-step explanation:

dilation scale factor 2: starting with δabc, draw the dilation image of the triangle with a center at the origin and a scale factor of two. notice that every coordinate of the original triangle has been multiplied by the scale factor (x2). dilation with scale factor 2, multiply by 2.