Question

Below is a square grid of 8$\times$8


What is total number of rectangles in the grid?

• A. $36\times 36$
• B. $35\times 35$
• C. $34\times 34$
• D. $32\times 32$

Answer 1

The correct option is A $36\times 36$

(In a grid of 8$\times$8, there will 9 horizontal lines and 9 vertical lines)

Hence total number of rectangles are

${=}^9{C}_2{\times }^9{C}_2=\left(\frac{9\times 8}{2}\right)\times \left(\frac{9\times 8}{2}\right)=36\times 36$

Hence option a is correct.