Question

area of
rectangle
square
triangle
parallelogram
circle
with diagram

Answer 1

Triangle
Area = ½ × b × h
b = base
h = vertical height Square
Area = a2
a = length of sideRectangle
Area = w × h
w = width
h = height Parallelogram
Area = b × h
b = base
h = vertical heightTrapezoid (US)
Trapezium (UK)
Area = ½(a+b) × h
h = vertical height Circle 
Area = π × r2
Circumference = 2 × π × r
r = radiusEllipse
Area =πab
 Sector
Area = ½ × r2 × θ 
r = radius
θ = angle in radians

Note: h is at right angles to b: