A'(- 4, 3 )
Under a counterclockwise rotation about the origin of 90°
a point (x, y ) → (- y, x )
A(3, 4 ) → A'(- 4, 3 )
Let the width =x
length = 6x
p=14x
28=14x
x=2
You would multiply the orignial price by (10%) converted to decimal to find the discount:
21 * 0.10
=2.10
Then, you subract the discount from the original price to see how much he paid:
21 - 2.10 = $18.90
648 cm
To find the volume of a rectangular prism (such as the one in the picture) you would do:
V=L*W*H
So plugging the numbers in:
V=18*12*3