The sides of a triangle measure $15 \text{ cm}$,$17 \text{ cm}$,and $20 \text{ cm}$. Then,the semi-perimeter of the triangle is ......... $\text{cm}$.

In quadrilateral $PQRS$,$PQ = 27 \, cm$,$QR = 30 \, cm$,$RS = 52 \, cm$,$SP = 53 \, cm$ and $PR = 51 \, cm$,then find the area of the quadrilateral in $cm^2$.

Each side of an equilateral triangle measures $10\,cm$. Find the semi-perimeter of the triangle. (in $,cm$)

From a point in the interior of an equilateral triangle,perpendiculars are drawn on the three sides. The lengths of the perpendiculars are $14 \, cm$,$10 \, cm$,and $6 \, cm$. Find the area of the triangle.

The sides of a quadrilateral $ABCD$ are $6 \, cm$,$8 \, cm$,$12 \, cm$,and $14 \, cm$ (taken in order) respectively,and the angle between the first two sides is a right angle. Find its area in $cm^2$.

Find the area of a triangle whose sides are $33 \, cm$,$34 \, cm$,and $65 \, cm$. (in $, cm^2$)