UPSC CDS 2 2020 Math Paper

The two sides of a tringle are 40 cm and 41cm and the perimeter of the triangle is 90 cm.
Hence, the third side of the triangle = 90 cm - (40 + 41 ) cm = 90 cm – 81 cm = 9 cm
Clearly,
⇒(40)2+(9)2=(41)2
Hence, the triangle is right angled triangle.
So, Area of triangle =

1

2

×40×9=180 cm2