Question

Q. On a plane, there are 5 parallel and equidistant horizontal lines and 5 parallel and equidistant vertical lines. How many squares and rectangles are made by these lines?

• A. 100
• B. 275
• C. 225
• D. 125

Answer 1

The correct option is A 100

Here $n=4$, as 4 squares will be formed in each row and each column of this Square-Matrix. $\therefore$Number of rectangles
$=[\frac{n+1}{2}{]}^2$

$=[\frac{4\times 5}{2}{]}^2={10}^2=100$