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The length (in cm) of the hypotenuse of a right angled triangle exceeds the length of one side by 2 cm and exceeds twice the length of other side by 1 cm. Find the length of each side. Also find the perimeter and the area of the triangle.

Quadratic Equations

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Answer

Let the lengths of the two sides other than hypotenuse be x cm and y cm

According to question,

Hypotenuse = x + 2 (in terms of 1st side)

Hypotenuse = 2y + 1 (in terms of 2nd side)

∴ x + 2 = 2y + 1
x = 2y + 1 - 2
x = 2y - 1

Hypotenuse = 2y + 1

As the given triangle is right-angled, by using Pythagoras theorem, we get:

x2+y2=(2y+1)2x^2 + y^2 = (2y + 1)^2

Putting value of x = 2y - 1 in above equation

(2y1)2+y2=(2y+1)24y2+14y+y2=4y2+1+4y4y24y2+y2+114y4y=0y28y=0y(y8)=0y=0 or y8=0y=0 or y=8\Rightarrow (2y - 1)^2 + y^2 = (2y + 1)^2 \\[1em] \Rightarrow 4y^2 + 1 - 4y + y^2 = 4y^2 + 1 + 4y \\[1em] \Rightarrow 4y^2 - 4y^2 + y^2 + 1 - 1 - 4y -4y = 0 \\[1em] \Rightarrow y^2 - 8y = 0 \\[1em] \Rightarrow y(y - 8) = 0 \\[1em] \Rightarrow y = 0 \text{ or } y - 8 = 0 \\[1em] y = 0 \text{ or } y = 8

y ≠ 0 , as that will make value of x negative and length cannot be negative.

∴ y = 8 , x = 2y - 1 = 15 , hypotenuse = 2y + 1 = 17

Perimeter = 8 + 15 + 17 = 40 cm

Area=12×first side × second side=12×8×15 cm2=60 cm2\text{Area} = \dfrac{1}{2} \times \text{first side } \times \text{ second side} \\[1em] = \dfrac{1}{2} \times 8 \times 15 \text{ cm}^2 \\[1em] = 60 \text{ cm}^2

Hence, the value of first side = 8cm, second side = 15 cm , Hypotenuse = 17cm , Perimeter = 40cm , Area = 60 cm2.

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