Mathematics
The perimeter of a right triangle is 60 cm and its hypotenuse is 25 cm. Find the area of the triangle.
Mensuration
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Answer
Let △ABC be the right triangle.

We know that,
Perimeter of a right-angled triangle = 60 cm
Hypotenuse = 25 cm
So, the sum of other two sides of triangle = 60 – 25 = 35 cm
Let, base (BC) = x cm
So, AB = (35 - x) cm
Using the Pythagoras theorem,
⇒ AC2 = AB2 + BC2
⇒ 252 = (35 - x)2 + x2
⇒ 625 = 1225 + x2 - 70x + x2
⇒ 2x2 - 70x + 600 = 0
Dividing by 2 on both sides,
⇒ x2 - 35x + 300 = 0
⇒ x2 - 15x - 20x + 300 = 0
⇒ x(x – 15) - 20(x - 15) = 0
⇒ (x - 15)(x - 20) = 0
⇒ x - 15 = 0 or x - 20 = 0
⇒ x = 15 or x = 20.
If x = 15, then 35 - x = 35 - 15 = 20 cm.
If x = 20, then 35 - x = 35 - 20 = 15 cm.
So, length of other two sides apart from hypotenuse are 15 cm and 20 cm.
Area of triangle = × base × height
Substituting the values we get,
A = × 15 × 20 = 150 cm2.
Hence, area of triangle = 150 cm2.
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