question_answer

The area of a rhombus, one side of which measures 20 cm and one diagonal 24 cm, is:

A) 256sq.cm                    

B) 384sq.cm

C) 512sq.cm                    

D) 480sq.cm

Correct Answer: B

Solution :

The diagonals of a rhombus are perpendicular bisector of each other \[={{a}^{3}}\]  \[=6{{a}^{2}}sq\] In right angle triangle OBC,                       \[=4{{a}^{2}}sq\] \[=\sqrt{3}a\]\[lbh\] \[=\sqrt{{{l}^{2}}+{{b}^{2}}+{{h}^{2}}}\] \[=2(lb+bh+hl)sq.\]  \[h=2h(l+b)\] The required area \[\text{=Area of base }\!\!\times\!\!\text{ height= }\!\!\pi\!\!\text{ }{{\text{r}}^{\text{2}}}\text{ }\!\!\times\!\!\text{ h= }\!\!\pi\!\!\text{ }{{\text{r}}^{\text{2}}}\text{h}\]