Mrs. Trout estimated her math class next year would include 28 students. The actual size of the class turned out to be 32 students. She calculated the percent error in the following way. 28 - 32 = -4

4
32
= 0.125%

Is Mrs. Trout correct? Explain why or why not.

Mrs. Trout set up the ratio correctly, but she forgot to multiply by 100 to get the correct percent.

x=9

step-by-step explanation:

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.