Question

Find the square of 225.

(a) 505625

(b) 49625

(c) 50625

(d) 51625

The question was posed to me in an internship interview.

This is a very interesting question from Finding the Square of a Number in section Squares and Square Roots of Mathematics – Class 8

Answer 1

Right choice is (c) 50625

Easy explanation: There is a beautiful pattern followed by all the numbers ending with 5. We can get the square of any number ending with 5 without actually calculating it. All the numbers ending with 5 shows 25 at the end of their squares, and the other places can be filled by multiplying the next consecutive number. For example: 225^2 = (22×23)25 i.e.50625 (the step shown is just for understanding).