asked 225k views
1 vote
A rectangle has an area of 114cm squared and a perimeter of 50 cm. What are its dimensions

asked
User Mosceo
by
9.4k points

1 Answer

5 votes

Answer:

width = 6

length = 9

Explanation:

Perimeter = 2(length + width) or P = 2(l + w)

2(l + w) = 50

l + w = 25

l = 25 - w

Area = length x width or A = lw

lw = 114

Substitute l = 25 - w into the lw = 114

(25 - w)w = 114

25w - w^2 = 114

-w^2 + 25w - 114 = 0

=> w^2 - 25w + 114 = 0

we have x = [-b ± √(b^2 - 4ac)] / 2a

w = [-(-25) ± √((-25)^2 - 4(1)(114)))] / 2(1)

w = [25 ± √(625 - 456)] / 2

w = [25 ± √(169)]/2

w = [25 ± 13]/2

w = [25 + 13]/2 = 38/2 = 14

or

w = [25 - 13]/2 = 12/2 = 6

if width = 14, length = 25 - 14 = 11

then area = 14 x 11 = 154, this is incorrect answer

if width = 6, length = 25 - 6 = 19

then area = 6 x 19 = 114, this is correct answer

answered
User Hawk
by
8.1k points
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