8th Class
Mathematics
Mensuration
Question Bank
Mensuration
question_answer
A tin sheet is in the form of a rhombus whose side is 5 cm and one of its diagonals is 8 cm. Then the cost of painting the sheet at the rate of \[x=4\pi {{r}^{2}}\] on both of its sides is:
A)Rs.84
B)Rs.140
C)Rs.168
D)none of these
Correct Answer:
C
Solution :
Diagonals of a rhombus bisect each other at\[T.S.A.=\frac{1}{2}pl+B\]. In \[=\frac{\text{1}}{\text{3}}\text{ }\!\!\times\!\!\text{ Area of base }\!\!\times\!\!\text{ Height}\] \[V=\frac{1}{3}Ah\] \[\frac{6}{5}th\] \[1520{{m}^{2}}\] Area of ABCD \[2520{{m}^{2}}\] Now, the cost of painting \[2420{{m}^{2}}\]area of rhombus ABCD \[215c{{m}^{2}}\]