Answer:
Explanation:
Find what you know.
Perimeter = 64cm
Length = width*3 + 8cm
Width = unknown (use w)
Perimeter of a rectangle formula is:
P = 2*L + 2*W or P = 2(L + W)
We know P and we have a formula for L
64cm = 2[(w*3 + 8cm) + w]
64cm = 2(3w + 8cm) + 2w
64cm = 6w + 16cm + 2w
Combine like terms:
64cm = 8w + 16cm
Subtract 16cm from both sides:
64cm - 16cm = 8w
48cm = 8w
Divide both sides by 8 to isolate the variable.
48cm/8 = w
6cm = w or swap them and w = 6cm
Now take the formula for perimeter again and plug in the value for width
64cm(P) = 2(L + 6cm(W))
64cm = 2L + 12cm
Subtract 12cm from both sides:
64cm - 12cm = 2L
52cm = 2L
Divide both sides by 2 to isolate the variable:
52cm/2 = L
26cm = L or swap them and L = 26cm
Rectangle is 26cm in length and 6cm in width. There is no height variable in a 2D rectangle, but sometimes (rarely) width is referred to as height. If this is a 3D box, than the height is equal to the width, in which case the information given might be slightly misleading.
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Donald S. answered • 01/06/15
TUTOR New to Wyzant
Interactive Chemical Educator for Chemistry
SEE TUTORS LIKE THIS
The perimeter = 2l + 2w
l = 3w+8
2l+2w = 64
2(3w+8)+2w = 64
6w+2w+16 = 64
8w + 16 = 64
8w = 48
w = 6 so l = 3(6)+8 = 26