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The adjoining figure shows a field with the measurement given in metres. Find the area of the field.

The adjoining figure shows a field with the measurement given in metres. Find the area of the field. ARC Properties of Circle, R.S. Aggarwal Mathematics Solutions ICSE Class 9.

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Answer

Calculating the area of triangle DXC,

Area of △DXC=12×CX×DX=12×30×12=15×12=180 m2.\text {Area of △DXC} = \dfrac{1}{2} \times CX \times DX \\[1em] = \dfrac{1}{2} \times 30 \times 12 \\[1em] = 15 \times 12 \\[1em] = 180 \text{ m}^2.

Calculating the area of trapezium CXZB,

Area of trapezium CXZB=12×(sum of parallel lines)×distance between them=12×(CX+BZ)×XZ=12×(30+25)×15=12×55×15=27.5×15=412.5 m2.\text {Area of trapezium CXZB} = \dfrac{1}{2} \times \text{(sum of parallel lines)} \times \text{distance between them} \\[1em] = \dfrac{1}{2} \times (CX + BZ) \times XZ \\[1em] = \dfrac{1}{2} \times (30 + 25) \times 15 \\[1em] = \dfrac{1}{2} \times 55 \times 15 \\[1em] = 27.5 \times 15 \\[1em] = 412.5 \text{ m}^2.

Calculating the area of triangle AZB,

Area of △ AZB=12× base × height =12×BZ×AZ=12×25×10=25×5=125 m2.\text {Area of △ AZB} = \dfrac{1}{2} \times \text{ base } \times \text{ height } \\[1em] = \dfrac{1}{2} \times BZ \times AZ \\[1em] = \dfrac{1}{2} \times 25 \times 10 \\[1em] = 25 \times 5 \\[1em] = 125 \text{ m}^2.

From figure,

AD = 12 + 15 + 10 = 37 m.

Calculating the area of triangle AED,

Area of △AED=12× base × height =12×AD×EY=12×37×20=37×10=370 m2.\text {Area of △AED} = \dfrac{1}{2} \times \text{ base } \times \text{ height } \\[1em] = \dfrac{1}{2} \times AD \times EY \\[1em] = \dfrac{1}{2} \times 37 \times 20 \\[1em] = 37 \times 10 \\[1em] = 370 \text{ m}^2.

Total area = 180 + 412.5 + 125 + 370 = 1087.5 m2.

Hence, area of the figure = 1087.5 m2.

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