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
(a) 5
(b) 4
(c) 3
(d) 25
Solution:
Here, AC and BD are two diagonals of the rectangle ABCD. So
$B D=\sqrt{(4-0)^{2}+(0-3)^{2}}$
$=\sqrt{(4)^{2}+(-3)^{2}}$
$=\sqrt{16+9}$
$=\sqrt{25}$
$=5$ units
Hence, the correct answer is option (a).