UKMT Junior Mathematical Challenge, 2016

A cyclic quadrilateral has all four vertices on the circumference of a circle. Brahmagupta (598–670AD) gave the following formula for the area, $A$, of a cyclic quadrilateral whose edges have lengths $a$, $b$, $c$, $d$: $A = \sqrt{(s-a)(s-b)(s-c)(s-d)}$, where $s$ is half of the perimeter of the quadrilateral. What is the area of the cyclic quadrilateral with sides of length 4 cm, 5 cm, 7 cm and 10 cm?

(A) $6\text{ cm}^2$ (B) $13\text{ cm}^2$ (C) $26\text{ cm}^2$ (D) $30\text{ cm}^2$ (E) $36\text{ cm}^2$