16. in the figure below, δabc is similar to δdef.

find the length of ef.
a. 10
b. 12
c. 18
d. 21

What is the standard form of -5x^2+2x^4-11+x^3+3x

Complete the steps, which describe how to find the area of the shaded portion of the circle. find the area of the sector by multiplying the area of the circle by the ratio of the to 360. subtract the area of the triangle from the area of the sector.

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25