$A$ floral design on a floor is made up of $16$ tiles which are triangular,the sides of the triangle being $9\, cm, 28\, cm$ and $35\, cm$ (see Fig.). Find the cost of polishing the tiles at the rate of $50p$ per $cm^2$.

There is a slide in a park. One of its side walls has been painted in some colour with a message "$KEEP$ $THE$ $PARK$ $GREEN$ $AND$ $CLEAN$". If the sides of the wall are $15 \, m$,$11 \, m$ and $6 \, m$,find the area painted in colour.

Find the area of a triangle,two sides of which are $8 \, cm$ and $11 \, cm$ and the perimeter is $32 \, cm$.

Students of a school staged a rally for a cleanliness campaign. They walked through the lanes in two groups. One group walked through the lanes $AB, BC$ and $CA$; while the other through $AC, CD$ and $DA$ (see Fig.). Then they cleaned the area enclosed within their lanes. If $AB = 9 \, m, BC = 40 \, m, CD = 15 \, m, DA = 28 \, m$ and $\angle B = 90^{\circ}$,which group cleaned more area and by how much (in $, m^2$)? Find the total area cleaned by the students (neglecting the width of the lanes).

$A$ park,in the shape of a quadrilateral $ABCD$,has $\angle C = 90^{\circ}$,$AB = 9 \, m$,$BC = 12 \, m$,$CD = 5 \, m$,and $AD = 8 \, m$. How much area does it occupy (in $, m^{2}$)?

Find the area of a quadrilateral $ABCD$ in which $AB = 3 \, cm, BC = 4 \, cm, CD = 4 \, cm, DA = 5 \, cm$ and $AC = 5 \, cm$. (in $, cm^2$)