A) ` 880
B) ` 1020
C) ` 960
D) ` 980
Correct Answer: C
Solution :
Let ABCD be a rhombus having sides A = BC = CD = DA = \[x\,cm\] Perimeter of rhombus \[=40\,cm\] [Given] \[\Rightarrow \]\[x+x+x+x=40\] \[\Rightarrow \]\[4x=40\] \[\Rightarrow \]\[x=10\] In \[\Delta ABC,\]let \[a=10\,cm,\,b=12\,cm\]and \[c=10\,cm\] Now, semi-perimeter of \[\Delta \Alpha \Beta C,s=\frac{a+b+c}{2}\] \[=\left( \frac{10+10+12}{2} \right)cm\,=\frac{32}{2}\,cm\,=16\,cm\] \[\therefore \] Area of \[\Delta ABC\] \[=\sqrt{16(16-10)(16-10)(16-12)}\,c{{m}^{2}}\] \[=\sqrt{16\times 6\times 6\times 4}\,c{{m}^{2}}=48\,c{{m}^{2}}\] \[=\sqrt{16\times 6\times 6\times 4}\,c{{m}^{2}}=48\,c{{m}^{2}}\] Now, area of the rhombus ABCD \[=2(Area\,of\,\Delta \Alpha \Beta C)=(2\times 48)\,c{{m}^{2}}=96\,c{{m}^{2}}\] \[\because \]Cost of painting the sheet of area \[1\,c{{m}^{2}}=\] ` 5 \[\therefore \]Cost of painting the sheet of area \[96\,c{{m}^{2}}=\]` \[(96\times 5)=\]` 480 Thus, the cost of painting the sheet on both sides = ` \[(2\times 480)=\]` 960You need to login to perform this action.
You will be redirected in
3 sec