Area and perimeter (GCSE)

Triangles, parallelograms, trapezia, compound shapes. Both tiers.

GCSE expects formulas for the standard shapes: triangle ½bh, parallelogram bh, trapezium ½(a+b)h, kite ½d₁d₂. Compound shapes split into rectangles and triangles.

Worked examples

Triangle base 6, height 4: area ½×6×4 = 12.

Trapezium parallel sides 5, 9, height 4: area ½(5+9)×4 = 28.

Kite diagonals 6, 8: area ½×6×8 = 24.

Frequently asked questions

Height in trig context?

Always perpendicular height — not slant length. Common error.

Compound shape strategy?

Split into recognisable pieces, sum the areas (or subtract for cut-outs).