Volume of a rectangular prism (cuboid) = length $\times$ breadth $\times$ height

Given : Perimeter of the given figure = 15 cm 
Let the length of the third side be x.
Perimeter of a figure = Sum of lengths of its sides = AB + BC + AC
$\Rightarrow$ 15 cm = 6 cm + 5 cm + x
$\Rightarrow$ 15 cm = 11 cm + x
$\Rightarrow$ x = 15 cm - 11 cm
$\Rightarrow$ x = 4 cm
Therefore, the third side is 4 cm long.

Given:
side of the square is $6cm$.
area of square = $sid{e}^2$
$\therefore$ Area of the given figure = $(6cm{)}^2$ = $36c{m}^2$

Area is the total space occupied by any 2D shape.
$\therefore$ To know the number of tiles required to cover a floor, we need to find the total space of the floor or the area of the floor first and then will have to divide this area by the area of one tile.
To find the amount of water in the lake we need to find the capacity or volume occupied by the lake.
To find the cost of fencing a ground we need to calculate the perimeter of the ground.
To find the amount of paint in a container we need to find the capacity of the container which is its volume. So we need to calculate its volume. 

Given: Volume of each block is $1c{m}^3$
There are 10 blocks in the given figure.
$\Rightarrow$ Volume of the object $=10\times 1c{m}^3=10c{m}^3$

Answer: Option C. ->

Given: Area of each small square = $1c{m}^2$
$\Rightarrow$ Area of figure in option A = $8c{m}^2$
    Area of figure in option B = $9c{m}^2$
    Area of figure in option C = $10c{m}^2$
    Area of figure in option D = $7c{m}^2$
$\therefore$ The figure in option C has the largest area. 
 

Given: Length of the side = 4 cm
Volume of the cube $=Side\times Side\times Side$
$=4cm\times 4cm\times 4cm$
$=64c{m}^3$
 

Given: Perimeter = Area (Numerically)
Perimeter of square $=4\times Side$
Area of square $=Side\times Side$
Perimeter = Area (Given)
$\Rightarrow$ $4\times Side$ $=Side\times Side$
$\Rightarrow$ $Side=4units$
$\therefore$ If the Perimeter and area of a square are equal, then the side is 4 units long.

Given: Side of the Square = 10 m 
Ali is running along the boundary of the park.
This implies that the distance covered by him will be equal to the perimeter of the park.
Perimeter of a square = 4 $\times$ Side
$\Rightarrow$ Perimeter of the square park = 4 $\times$ 10 m
= 40 m
Distance covered by Ali in two rounds of the park = 2 $\times$ Perimeter of the park
= 2 $\times$ 40 m
= 80 m
Therefore, distance covered by Ali is 80 m.