Find the Area of Similar Shapes

Are monsters good at maths?

Not unless you Count Dracula!

The type of questions involving area scale factor can appear monstrous.

Honestly, they're not!

           4 cm                                                            8 cm

          Area 16 cm²                                     What is the area of this square?

1.  Find the scale factor of the enlargement:  8 ÷ 4  =  scale factor 2     This does not mean that the area is twice as big!!

2.  Take the scale factor and square it to find the area scale factor:  2² = 4

3. The area of the larger square is 4 times as big: 16 x 4 = 64 cm²

             6  cm                                                      18 cm

  Area = 12 cm²                                        What is the area of this rectangle?

1.  Find the scale factor of the enlargement:   18 ÷ 6  =  scale factor 3    This does not mean that the area is 3 times as large.

2.  Take the scale factor and square it: 3² = 9

3. The area of the larger rectangle is 9 times as big:  12 x 9 = 108 cm²

Can you spot the pattern when you see it in the form of a table?

Study the table below and then move on to the questions.