
Sarah K. answered 03/28/19
Tutor for the SAT for over 10 years
A rectangle has four sides: top and bottom (same size) and left/right sides (same size).
Perimeter is adding all four sides together. Therefore, you have length + length + width + width
We are given that length (L) = 3x+4 and width (W) = 2x+7
a) If Perimeter (P) = L + L + W + W = 2L + 2W then
P = 2(3x+4) + 2(2x+7) Simplify
P = 6x+8 + 4x+14 Combine like terms
P = 6x+4x + 24+14
P = 10x + 22
b) If Perimeter (P) = 62 then what is x in equation a)?
P = 10x + 22
62 = 10x + 22
62 - 22 = 10x
40 = 10x
40/10 = x
4 = x
c) Find the lengths and widths.
We know the equation for length (L) = 3x+4 and we know that x= 4 so let's plug that in
L = 3x + 4
L = 3(4) + 4
L = 12 + 4
L = 16
Repeat for width.
W = 2x+7
W = 2(4) + 7
W = 8 + 7
W = 15
Check to see if 15+15+16+16 = the perimeter given (62)
15+15+16+16 = 62, yes
Kit M.
THANK YOU SO MUCH ♥️03/28/19