Question

Given that ABCD is a rectangle as shown in the figure, AC = $\times$ OB

Answer 1

In the figure shown, ABCD is a rectangle with AC and BD as diagonals.

We know that in a rectangle, diagonals bisect each other, that is, AC bisects BD and vice versa. In this case, O is the midpoint of both AC and BD (because they bisect each other). So, 2 $\times$ OB = BD and since BD = AC, we have, AC = BD = 2 $\times$ OB.