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Calculate the area of the figure given below which is not drawn to scale.

Calculate the area of the figure given below which is not drawn to scale. Area and Perimeter of Plane Figures, Concise Mathematics Solutions ICSE Class 9.

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Answer

Area of figure ABCEF = Area of trapezium ABCF + Area of triangle CEF

Calculate the area of the figure given below which is not drawn to scale. Area and Perimeter of Plane Figures, Concise Mathematics Solutions ICSE Class 9.

Area of triangle CEF = 12\dfrac{1}{2} x b x h = 12\dfrac{1}{2} x CF x DE

= 12\dfrac{1}{2} x 25 x 12 m2

= 25 x 6 m2

= 150 m2

In triangle BGC,

Base2 + Height2 = Hypotenuse2

⇒ CG2 + BG2 = CB2

Let h be the length of BG.

⇒ 102 + h2 = 262 (∵CG = CF - GF = CF - BA = 25 - 15 = 10)

⇒ 100 + h2 = 676

⇒ h2 = 676 - 100

⇒ h2 = 576

⇒ h = 576\sqrt{576}

⇒ h = 24 cm

Area of trapezium = 12\dfrac{1}{2} (sum of parallel sides) x distance between the parallel sides

= 12\dfrac{1}{2} (AB + CF) x BG

= 12\dfrac{1}{2} (15 + 25) x 24 m2

= 12\dfrac{1}{2} x 40 x 24 m2

= 20 x 24 m2

= 480 m2

So, total area of figure ABCEF = 150 + 480 m2

= 630 m2

Hence, the area is 630 m2.

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