Mensuration
3.1 – Area
Area of a Rectangle:
Length × Width
l×w
Area of a Trapezium:
½ (Base1 + Base2) × Height
½ (a + b) h
Area of a Kite:
½ (Diagonal1 × Diagonal2)
½ (a × b)
Area of a Triangle:
½ (Base × Height)
½ (b × h)
OR
½ (a × b) sin C
Area of a Parallelogram:
Base × Height
b×h
OR
(b × a) sin θ
3.2 – The Circle
Circumference of a Circle:
Circumference = π × diameter
which is πd
OR
Circumference = 2 × π × radius
which is 2πr
Area of a Circle:
Area = π × radius²
which is πr²
3.3 – Arc Length and Sector Area
Arc Length:
Arc Length = θ/360 × 2 × π × radius
which is θ/360 × 2πr
Sector Area:
Sector Area = θ/360 × π × radius²
which is θ/360 × πr²
3.4 – Volume
Volume of a Prism:
Volume = (area of cross section) × length
which is A × l
Volume of a Cylinder:
Volume = (area of cross section) × length
Volume = π × radius² × height
which is πr²h
Volume of a Pyramid:
Volume = 1/3 × (base area) × height
which is 1/3 × A × h
Volume of a Cone:
Volume = 1/3 × π × radius² × height
which is 1/3 πr²h
Volume of a Sphere:
Volume = 4/3 × π × radius³
which is 4/3 πr³
3.5 – Surface Area
Cylinder:
Curved Surface Area = 2 × π × radius × height
2πrh
Total Surface Area = (2 × π × radius × height) + (2 × π × radius²)
2πrh + 2πr²
Sphere:
Surface Area = 4 × π × radius²
4πr²
Cone:
Curved Surface Area = π × radius × slant height
πrl
Total Surface Area = (π × radius × slant height) + (π × radius²)
πrl + πr²