1. The problem is to understand the chapter "Mensuration" which deals with measuring the surface area and volume of different geometric shapes. 2. Mensuration formulas are used to calculate areas and volumes of 2D and 3D shapes respectively. 3. Important formulas include: - Area of rectangle: $A = l \times w$ - Area of square: $A = a^2$ - Area of triangle: $A = \frac{1}{2} \times base \times height$ - Surface area of cube: $SA = 6a^2$ - Surface area of cuboid: $SA = 2(lw + lh + wh)$ - Volume of cube: $V = a^3$ - Volume of cuboid: $V = l \times w \times h$ - Surface area of sphere: $SA = 4\pi r^2$ - Volume of sphere: $V = \frac{4}{3} \pi r^3$ 4. To solve exercises, identify the shape, write down given dimensions, apply the correct formula, and simplify step-by-step. 5. Example: Find the volume of a cuboid with length 5, width 3, and height 4. - Use formula $V = l \times w \times h$ - Substitute values: $V = 5 \times 3 \times 4$ - Calculate: $V = 60$ 6. This means the volume of the cuboid is 60 cubic units. 7. Always remember to keep units consistent and convert if necessary. This explanation covers the basics and approach to all exercises in the Mensuration chapter.