In the following figures, find the area of the shaded portions:
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AcademicMathematicsNCERTClass 7

$(i)$ Area of the rectangle$= l\times b$

$=18cm\times\left(6cm+4cm\right)$

$=18cm\times10cm=180cm^2$

Area of the right $\Delta BCE=\frac{1}{2}\times b\times h$

$=\frac{1}{2}\times8\times10=40\ cm^2$

Area of the shaded portion

$=180cm^2-70cm^2=110cm^2$

$(ii)$. Area of the square $PQRS= \left(Side\right)^2$

$=\left(20\right)^2=400cm^2$

Area of triangle$=\ \frac{1}{2}\times b\times h$

$\frac{1}{2}\times10\times10=50cm^2$ 

Area of triangle$=\ \frac{1}{2}\times b\times h$

$=\frac{1}{2}\times10\times20=100cm^2$

Area of triangle$=\ \frac{1}{2}\times b\times h$

$=\frac{1}{2}\times10\times20=100cm^2$
 
Area of the three triangles

$=50cm^2+100cm^2+100cm^2=250cm^2$

Area of the shaded portion

$=400cm^2-250cm^2=150cm^2$
raja
Updated on 10-Oct-2022 13:36:08

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