The lengths of the two sides of a right triangle containing the right angle differ by 2 cm. If the area of the triangles 24 cm2, find the perimeter of the triangle.
Let the sides at right angles be a and b
And, the third side be c.
Given: a-b = 2 cm
Area of triangle = 24 cm2
Now, since a-b = 2
⇒ a = b + 2
Now we know that,
Area of triangle = 1/2 × base × height
⇒ 24 = 1/2 × b × (b + 2)
⇒ 24 × 2 = b2 + 2b
⇒ b2 + 2b = 48
⇒ b2 + 2b-48 = 0
⇒ b2 + 8b-6b-48 = 0
⇒ b(b + 8)-6(b + 8) = 0
⇒ (b + 8)(b-6) = 0
This gives us two equations,
i. b + 8 = 0
⇒ b = -8
ii. b-6 = 0
⇒ b = 6
Since, the side of the triangle cannot be negative
Therefore, b = 6 cm
⇒ a = (b + 2) cm
⇒ a = (6 + 2) cm
⇒ a = 8 cm
Now we know that,
Base2 + Perpendicular2 = Hypotenuse2
⇒ a2 + b2 = c2
⇒ 82 + 62 = c2
⇒ c2 = 64 + 36
⇒ c2 = 100
⇒ c = 10
Now,
Perimeter of triangle = a + b + c
⇒ Perimeter of triangle = 8 + 6 + 10
⇒ Perimeter of triangle = 24 cm