(7.5 × 7.5 + 37.5 + 2.5 × 2.5) is equal to :  Choose the correct choice from the following answers.
A) 30 B) 60 C) 80 D) 100 E) None of these
Solution   Given expression = (7.5 × 7.5 + 2 × 7.5 × 2.5 + 2.5 × 2.5)   =(a 2 + 2ab + b 2) = (a + b)2 = (7.5 + 2.5)2 = 102 = 100 . Answer 100
<result>D</result>
(7.5 × 7.5 + 37.5 + 2.5 × 2.5) is equal to :