RS Aggarwal Maths Area of a Trapezium and a Polygon Solutions
FAQs on Class 8 RS Aggarwal Maths Area of a Trapezium and a Polygon Solutions - Free PDF Download
1. What is the step-by-step method to find the area of a trapezium as explained in RS Aggarwal Class 8 Maths Chapter 18 solutions?
The solutions for RS Aggarwal Class 8 Maths Chapter 18 consistently apply a clear, step-by-step method to find the area of a trapezium. The approach follows the standard formula and involves these steps:
Identify the parallel sides: First, identify the two parallel sides of the trapezium (often denoted as 'a' and 'b').
Determine the height: Next, identify the perpendicular distance between these parallel sides, which is the height ('h') of the trapezium.
Apply the formula: Substitute these values into the formula for the area of a trapezium, which is Area = 1/2 × (sum of parallel sides) × height.
Calculate the final answer: Perform the calculation to arrive at the final area, ensuring the unit is squared (e.g., cm², m²).
2. How do the RS Aggarwal solutions for Chapter 18 demonstrate finding the area of a complex polygon?
The solutions demonstrate a powerful technique for finding the area of any complex or irregular polygon. The method involves decomposing the polygon into simpler, standard shapes whose areas are easy to calculate. This is done by drawing one or more diagonals or perpendiculars. The polygon is typically broken down into a combination of:
Triangles
Rectangles
Trapeziums
The area of each of these simple shapes is calculated individually. Finally, the total area of the polygon is found by adding the areas of all these constituent shapes together.
3. Are the solutions for all exercises in Chapter 18, such as 18A, 18B, and 18C, available?
Yes, the RS Aggarwal solutions for Class 8 Maths Chapter 18 provide comprehensive, question-by-question solutions for all the exercises in the chapter. This includes detailed walkthroughs for problems in Exercise 18A, Exercise 18B, and Exercise 18C. Each solution is crafted to align with the CBSE 2025-26 curriculum guidelines, ensuring students understand the correct methodology for every problem type.
4. Why is it crucial to identify the correct 'height' of a trapezium, and how do the solutions clarify this?
Identifying the correct height is crucial because the area formula depends on the perpendicular distance between the parallel sides. A common mistake is to use the length of a slanted, non-parallel side as the height, which leads to an incorrect answer. The solutions clarify this by explicitly stating the height in each problem and often illustrating it in diagrams. This reinforces the concept that the height must form a right angle (90°) with the two parallel bases, regardless of how the trapezium is oriented.
5. How does the method for finding the area of a rhombus differ from that of a general quadrilateral in the Chapter 18 solutions?
The solutions in Chapter 18 showcase distinct methods based on the properties of the shapes.
For a rhombus, which is a special quadrilateral with equal sides and perpendicular diagonals, a specific formula is used: Area = 1/2 × (product of the lengths of the diagonals) or A = 1/2 × d₁ × d₂.
For a general quadrilateral, where diagonals may not be perpendicular, the method involves knowing the length of one diagonal and the lengths of the perpendiculars drawn to it from the opposite vertices. The area is then the sum of the areas of the two triangles formed by that diagonal.
The solutions carefully select the most efficient formula based on the given parameters for each shape.
6. What is the underlying principle for finding the area of any polygon by dividing it into simpler shapes?
The fundamental principle demonstrated in the solutions is the Area Addition Postulate. This mathematical concept states that the area of a whole figure is the sum of the areas of its non-overlapping parts. By breaking down a complex polygon (like a pentagon or hexagon) into familiar shapes such as triangles and trapeziums, we can calculate the area of each part separately. Since these parts do not overlap, adding their individual areas gives the exact total area of the original complex polygon. This method transforms a difficult problem into a series of simpler, manageable calculations.
7. What are the key formulas from Chapter 18 that a Class 8 student must master for exams?
Based on the problems solved in RS Aggarwal Chapter 18, a student must master the following key formulas for their exams:
Area of a Trapezium: 1/2 × (Sum of parallel sides) × Height
Area of a General Quadrilateral: 1/2 × Diagonal × (Sum of the heights of the two triangles formed)
Area of a Rhombus: 1/2 × (Product of its diagonals)
Mastering the application of these three formulas is essential for solving almost every question in this chapter.











