A 3D shape with a circular cross-section is ... Image caption, First work out the area of the triangular faces. The area of a triangle is ½ × base × height. There are two congruent (identical ...

The area of the rectangle is 8 cm 2. Two triangles make the rectangle. The area of one triangle is half the area of the rectangle. \(8 \div 2 = 4~\text{cm}^2\) The area of a triangle can also be ...