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Radha Made a Picture of an Aeroplane with Coloured Papers as Shown in the Given Figure. Find the Total Area of the Paper Used. - CBSE Class 9 - Mathematics

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Question

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) cm= 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

  Is there an error in this question or solution?

APPEARS IN

 NCERT Solution for Mathematics Class 9 (2018 to Current)
Chapter 12: Heron's Formula
Ex. 12.20 | Q: 3 | Page no. 206

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Solution Radha Made a Picture of an Aeroplane with Coloured Papers as Shown in the Given Figure. Find the Total Area of the Paper Used. Concept: Application of Heron’S Formula in Finding Areas of Quadrilaterals.
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