Question

Q.11 Find the Square Ending With"5.
1.
852
2.
152
3.
352
4.
7052
5.
115​

Answer 1

5.115

.... ...

Squares of Numbers That End in 5

A number that ends in 5 has the form A = 10a + 5, where a has one digit less than A. To find the square A² of A, append 25 to the product a×(a + 1) of a with its successor. For example, compute 115². 115 = 11·10 + 5, so that a = 11. First compute 11·(11 + 1) = 11·12 = 132 (since 3 = 1 + 2). Next, append 25 to the right of 132 to get 13225!