question_answer

If one side and one diagonal of a rhombus are 13 cm and 10 cm, its area in sq. cm. is :

A) 240                    

B)         200

C) 120   

D)        140

E) None of these

Correct Answer: C

Solution :

Explanation Option [c] is correct. Let ABCD be rhombus. \[\operatorname{AB}=13 cm,\] \[\operatorname{BD}=10 cm\] \[\operatorname{OB}=\frac{10}{2}= 5\,cm\] \[\therefore \,\,\,\,AO\,=\sqrt{169-25}\] \[=12\,cm\] \[\therefore \,\,\,\,AC\,=24\,cm\] \[\therefore \,\,\,\,Area\,\,of\,rhombus\,\] \[=\frac{1}{2}\times (24\times 10)=120\,sq.\,cm.\]