A) 42 \[c{{m}^{2}}\]
B) 60 \[c{{m}^{2}}\]
C) 84 \[c{{m}^{2}}\]
D) 96 \[c{{m}^{2}}\]
Correct Answer: C
Solution :
(c): Area of parallelogram ABCD = Area of 2 \[\Delta ABC\] Semi- perimeter of \[\Delta ABC,S=\frac{20+7+15}{2}={{\frac{42}{2}}^{~}}=21cm\] \[\therefore \]area of \[\Delta ABC=\sqrt{s\left( s-a \right)\left( s-b \right)\left( s-c \right)}\] \[=\sqrt{21\left( 21-7 \right)\left( 21-20 \right)\left( 21-15 \right)}\] \[=\sqrt{21\times 14\times 6}=42\]sq.cm. \[\therefore \]Area of parallelogram \[=2\times 42=84\]sq. cm.You need to login to perform this action.
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