1. The problem is to learn the basic mensuration formulas used in class 8 for calculating areas and volumes of common geometric shapes. 2. Mensuration involves formulas to find the area, surface area, and volume of 2D and 3D shapes. 3. Important formulas include: - Area of rectangle: $A = l \times w$ - Area of square: $A = a^2$ - Area of triangle: $A = \frac{1}{2} \times b \times h$ - Area of circle: $A = \pi r^2$ - Circumference of circle: $C = 2 \pi r$ - Surface area of cube: $SA = 6a^2$ - Surface area of cuboid: $SA = 2(lw + lh + wh)$ - Surface area of sphere: $SA = 4 \pi r^2$ - Surface area of cylinder: $SA = 2 \pi r(h + r)$ - Volume of cube: $V = a^3$ - Volume of cuboid: $V = l \times w \times h$ - Volume of sphere: $V = \frac{4}{3} \pi r^3$ - Volume of cylinder: $V = \pi r^2 h$ 4. Here, $l$ = length, $w$ = width, $h$ = height, $a$ = side length, $b$ = base, $r$ = radius, and $\pi \approx 3.1416$. 5. These formulas help calculate the size and capacity of shapes in practical problems. 6. Always remember to use consistent units and convert if necessary before applying formulas. This summary covers the essential mensuration formulas for class 8.