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what is the lengths of a right triangle if the hypotenuse is 12 and the area of the triangle 24?

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2 Answers

The formula for area of a triangle is A=b*h/2, where b and h base and height of a triangle. In the case of a right triangle, they are the legs. So we have two unknowns and 2 equations.
 
24=b*h/2
b^2 + h^2 = 144   (Pythagorean theorem)
 
Solve the first equation for either b or h and substitute into the second.
 
24=b*h/2
48=b*h  (multiply both sides by 2)
b=48/h   (divide both sides by h)
 
(48/h)^2 + h^2 = 144 (substitute 48/h for b)
2304/h^2 + h^2 = 144
2304/h^2 + h^4/h^2 = 144  (find common denominator for left side)
2304 + h^4 = 144*h^2   (multiply both sides by h^2)
 
This is really a quadratic equation. You can make this clearer by letting x = h^2
 
2304 + x^2 = 144x
x^2 - 144x + 2304 = 0
 
Use the quadratic formula to solve.
 
x = (144 ± sqrt((-144)^2-4*1*2304)))/2 ≈ 125.665, 18.334
If x = h^2 then sqrt(x) = h
h ≈ 11.210 or 4.282
 
Then plug into b = 48/h to get b. You'll find that if you choose 11.210 for h you'll bet 4.282 for b and if you choose 4.282 for h you'll get 11.210 for b.
 
So the legs of the triangle are approximately 4.282 and 11.210 inches.
 
Thanks for the interesting problem.
Area of a triangle is (B * H)/2 
The area is 24   .---- B*H=48 ---- B=48/H
 
the hypotenuse is 12^2=B^2+H^2
Replace B by (48 / H)
(48 / H)^2 + H^2 = 144
Now you just have to solve it to find H.
When you find H, you will be able to solve for B with this equation B=48/H
 

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