A kite in the shape of a square with a diagonal 32 cm and an isosceles triangles of base 8 cm and sides 6 cm each is to be made of three different shades as shown in the given figure. How much paper of each shade has been used in it?
Solution
We know that
Area of square = 1/2(diagonal)2
`"Area of the given kite "= 1/2(32 cm)^2 = 512 cm^2`
Area of 1st shade = Area of 2nd shade = 512/2 = 256 cm2
Therefore, the area of paper required in each shape is 256 cm2.
For IIIrd triangle
Semi-perimeter,
`s=(6+6+8)/2=10 cm`
By Heron’s formula,
`"Area of triangle "=sqrt(s(s-a)(s-b)(s-c))`
`"Area of 3rd triangle "=sqrt(10(10-6)(10-6)(10-8))`
`=(sqrt(10xx4xx4xx2))cm^2`
`=(4xx2sqrt5)cm^2`
`=8sqrt5 cm^2`
= (8 x 2.24) cm2
= 17.92 cm2
Area of paper required for IIIrd shade = 17.92 cm2