The perimeter and area of triangles, quadrilaterals (rectangle, parallelogram, rhombus, kite and square), circles, arcs, sectors and composite shapes can all be calculated using relevant formulae.

Area of a triangle is half the product of its base and height. Therefore, to calculate the area of a triangle, one should have its base and height measurements. Area of Triangle = ½ * b* h sq units ...

JEAN E. KILMER, Triangles of Equal Area and Perimeter and Inscribed Circles, The Mathematics Teacher, Vol. 81, No. 1 (JANUARY 1988), pp. 65-70 ...

Example A photo has dimensions 8 cm × 10 cm. An enlargement of this photo has an area of 320 cm 2. Find the ratio of the areas and the hence the dimensions of the enlarged photo. Solution Area of ...