Perimeter and area of squares and rectangle

Each interior angle of a regular polygon is 18^o more than eight times an enterior angle. The number of sides of the polygon is -

Derive the formula $2(l+b)$

If the length of rectangle, $AB$ is $10$ units and breadth, $BC$ is $16$ units.

Find the area of triangle $ADC$.

If the length of rectangle, $AB$ is $5$ units and breadth, $BC$ is $8$ units.

Find the area of triangle $ABC$.

Find the area of a square park in $\left({\mathrm{m}}^2\right)$ whose perimeter is $500 \mathrm{m}$

There will be no change in the area of an equilateral triangle when the perimeter of an equilateral triangle is doubled.

Find the area of of congruent parts of the rectangle. 

Find the area of of congruent parts of the rectangle. 

What happens to the area of a square if the perimeter of a square is doubled?

Find the area of of congruent parts of the rectangle. 

Find the area of congruent parts of the rectangle. 

Find the area of of congruent parts of the rectangle. 

The area of an equilateral triangle is $28 {\mathrm{m}}^2$. Find the perimeter in ($\mathrm{m}$) of an equilateral triangle.

Perimeter of a square is $144 \mathrm{c}\mathrm{m}$. What is its length?

Count the squares in figure and write its area.

Area of MNRS $=$ _____ $\mathrm{sq}.\mathrm{cm}$

The length and the breadth of a rectangular playground are $116$ metres and $77$ metres respectively. What distance will a boy cover in walking around the playground three times? If the answer is $K metres$ , then write the value of $K$ in the answer box.

A square garden is $172$ metres long. How much wire will be needed for fencing around it two times? If the answer is $K metres$ , then write the value of $K$ in the answer box.

A rectangular piece of ground is $30$ $\mathrm{m}$ long and $25$ $\mathrm{m}$ wide. Find the total length of the boundary wall needed to fence this ground. If the answer is $K m$ , then write the value of $K$ in the answer box.

Rakesh wants to frame a picture which is $45$ $\mathrm{cm}$ long and $15$ $\mathrm{cm}$ wide. How much wooden stick will he need? If the answer is $K cm$ , then write the value of $K$ in the answer box.

Find the perimeter of the square having side $12\mathrm{cm}$ .