Question

ABCD is a rectangle whose three vertices are B (4,0), C (4,3) and D (0, 3). The length of one of its diagonals is [CBSE 2014]
(a) 5
(b) 4
(c) 3
(d) 25

Answer 1

BD = $\sqrt{{\left(0-4\right)}^2+{\left(3-0\right)}^2}$
$$\begin{gathered} =\sqrt{4^2+3^2} \\ =\sqrt{25} \\ =5\mathrm{units} \end{gathered}$$
Hence, the correct answer is option (a).