01 Key Concepts
Area of a Rectangle
Area = length x width.
Area of a Triangle
Area = (1/2) x base x height.
Area of a Parallelogram
Area = base x height (the perpendicular height, not the slanted side).
Area of a Trapezoid
Area = (1/2) x (base1 + base2) x height — the average of the two parallel sides, times the height.
Area of a Circle
Area = pi x r^2, where r is the radius.
02 Key Formulas
- Rectangle: A = length * width
- Triangle: A = (1/2) * base * height
- Parallelogram: A = base * height
- Trapezoid: A = (1/2) * (base1+base2) * height
- Circle: A = pi * r^2
03 Solved Examples
Example 1 Find the area of a rectangle with length 8 and width 5.
- Apply the formula: A = length*width = 8*5.
Answer: 40 square units
Example 2 Find the area of a triangle with base 10 and height 6.
- Apply the formula: A = (1/2)*base*height = 0.5*10*6.
Answer: 30 square units
Example 3 Find the area of a trapezoid with parallel sides 4 and 8, and height 5.
- Apply the formula: A = (1/2)*(base1+base2)*height = 0.5*(4+8)*5.
- = 0.5*12*5.
Answer: 30 square units
04 Practice Questions
1Find the area of a rectangle with length 12 and width 4.
48
2Find the area of a triangle with base 8 and height 5.
20
3Find the area of a parallelogram with base 6 and height 9.
54
4Find the area of a trapezoid with bases 3 and 7, height 4.
20
5Find the area of a circle with radius 2 (pi~3.14).
12.56
📄 Area — Downloadable Worksheet
10 questions with a full answer key. Grab the PDF to print, or try the interactive version in your browser.