Question

pls explain the solution ​

Answer 1

Here they directly gave the digits after calculation. So, the formula used here us

$\sqrt{s (s - a )(s - b)(s - c)}$

where s is the semi-peimeter of the triangle and a, b and c are sides of the same triangle.

In ΔABD, a=24, b=13, c=13

s=24+13+13/2

=25

area of ΔABD=

$\sqrt[]{25(25 - 24)(25 - 13)(25 - 13)}$

=25×1×12×12

Similar explanation is also for the ΔBCD.

drop your doubts in the comments!