For a triangle,$a = 15 \, cm$,$b = 20 \, cm$ and $s = 31 \, cm$,find the value of $c$.

The base of a right triangle is $8 \, cm$ and its hypotenuse is $10 \, cm$. Its area will be (in $cm^2$):

Area of a trapezium $=$ .........

There is a triangular party plot with side lengths of $200\,m$,$210\,m$,and $290\,m$. Calculate the cost of raising a lawn in that plot at the rate of Rs. $5/m^2$.

The sides of a triangle are $56 \ cm$,$60 \ cm$,and $52 \ cm$ long. Then the area of the triangle is (in $cm^2$)

An isosceles triangle has a perimeter of $50\,cm$ and each of the equal sides is $17\,cm$. Find the area of the triangle. (in $,cm^2$)