If the area of an isosceles triangle whose base is $18 \mathrm{cm}$ and one of its equal sides is $15 \mathrm{cm}$, is $A {\mathrm{cm}}^2$, then find the value of $A$.

Find the area of the shaded portion.

If the area of the shaded portion is $k m^2$. Then find the value of $k$.

If the area of the shaded portion is $k {\mathrm{m}}^2$, write the value of $k$.

If the area of the shaded portion is $k {\mathrm{m}}^2$, write the value of $k$.