When we look at shapes, sometimes we wonder are they of the same size or area? With basic geometric understanding, we will be in a better position to deduce the answer just by comparing the shapes in question.
Look at the pairs of shapes below (Diagram A to E), and tell whether are they of the same surface area.
Visually some pairs may look bigger or smaller.
However, knowing the concept of area and combination of shapes, we can tell that only the pair of shapes in Diagram D will be different. All rest remain, even for the last digram E.
Diagram E can be easily deduced to have the same area by pasting the curvy (upper) part to the (lower) blank curvy profile, and likewise for the other half of the shape.
Shapes are InteResTing, am I correct?