Three sides of a triangular field are $20\, m$,$21\, m$,and $29\, m$ long,respectively. The area of the field is.......$m^2$.

If the two diagonals of a parallelogram are $72 \, cm$ and $30 \, cm$ respectively,then find its perimeter in $cm$.

If all the sides of a triangle are increased by $200 \%$,then the area of the triangle will increase by (in $\%$):

$A$ bed of roses is shaped as shown in the figure below. In the centre is a square and on each side there is a semi-circle. The side of the square is $21 \, m$. If each rose plant needs $6 \, m^{2}$ of space,then the number of plants in the bed is?

$A$ square is inscribed in a circle whose radius is $4\, cm$. The area of the portion between the circle and the square is

The angles of a quadrilateral are in the ratio of $2: 4: 7: 5$. The smallest angle of the quadrilateral is equal to the smallest angle of a triangle. One of the angles of the triangle is twice the smallest angle of the triangle. What is the second largest angle of the triangle? (in $^o$)