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A rectangle's area is 12cm and its diagonal is 5cm.

What are the sides of the rectangle? but with quadratic formula not Pythagorean Theorem

User Monokh
by
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2 Answers

5 votes

Answer:

Explanation:

ax2 + bx + c = 0

User SethRocker
by
8.0k points
5 votes

Answer:

Sides of the rectangle are 3 and 4

Explanation:

x=width

y=length

Area = xy = 12

x = 12/y plug this in to the next equation

x² + y² = 5² = 25

(12/y)² + y² = 25

144/y² + y² = 25 multiply by y² on both sides

144 + y⁴ = 25y² rewrite the equation

y⁴ -25y² + 144 = 0

rewrite with z=y² and z²=y⁴

z² - 25z + 144 = 0 now you can use the quadratic formula to find the roots of z (a=1, b=-25, c=144). Consider only the positive roots of z:

z = 16, 9

z = y² = 16, 9

y = √16, √9

y = 4, 3

x = 12/4 = 3

x = 12/3 = 4

x = 4 = length

y = 3 = width

User SkRoR
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8.1k points