Radha made a picture of an aeroplane with coloured papers as shown in the given figure. Find the total area of the paper used.
Solution
For triangle I
This triangle is an isosceles triangle.
Perimeter = 2s = (5 + 5 + 1) cm = 11cm
s = 11/2 = 5.5 cm
`"Area of triangle "=sqrt(s(s-a)(s-b)(s-c))`
`=[sqrt(5.5(5.5-5)(5.5-5)(5.5-1))]cm^2`
`=[sqrt((5.5)(0.5)(0.5)(4.5))]cm^2`
`=0.75sqrt11cm^2`
= (0.75 x 3.317) cm2
= 2.488 cm2 (Approximately)
For quadrilateral II
This quadrilateral is a rectangle.
Area = l × b = (6.5 × 1) cm2 = 6.5 cm2
For quadrilateral III
This quadrilateral is a trapezium.
`"Perpendicular height of parallelogram "=(sqrt(1^2-(0.5)^2))cm = sqrt0.75 cm = 0.866 cm`
Area = Area of parallelogram + Area of equilateral triangle
`=(0.866)1+sqrt3/4(1)^2`
= 0.866 + 0.433
= 1.299 cm2
Area of triangle (IV) = Area of triangle in (V)
`=(1/2xx1.5xx6)cm^2`
= 4.5 cm2
Total area of the paper used = 2.488 + 6.5 + 1.299 + 4.5 × 2
= 19.287 cm2