SEAMO 2027 - Paper C - SET 02 - Self-study Question 2

In triangle $ABC$, $AB=AC$. Points $M$ and $N$ are the midpoints of $AB$ and $AC$, respectively, and $D,E$ lie on $BC$, as shown. Given $AB=13$ cm, $BC=10$ cm and $DE=5$ cm, find the total area of the shaded regions, in $\text{cm}^2$.