Which statement explains how you could use coordinate geometry to prove the diagonals of a quadrilateral are perpendicular?
use the slope formula to prove the slopes of the diagonals are the same.
use the slope formula to prove the slopes of the diagonals are opposite reciprocals.
use the distance formula to prove the lengths of the diagonals are the same.
use the distance formula to prove the midpoints of the diagonals are the same.

option b is correct.

step-by-step explanation:

we have to prove that diagonals of a quadrilateral are perpendicular

the diagonals are perpendicular if the slopes of the diagonals are:

m₁ = -1/m

so, use the slope formula to prove the slopes of the diagonals are opposite reciprocals.

hence option b is correct.

to find the unit price, we must figure out the cost of one item (in this case one dish towel).   to do this, we divide the total price ($7.92) by the number of items bought (for this problem it is 8, because there are eight dish towels in one pack).  

$7.92/8 = $0.99

therefore, the unit price, or the price of one dish towel, is $0.99.

hope this !