Finding the Area of a Composite Shape

I have a BKSB question from the workbooks for Perimeter And Area that I don't understand how to work out.

Finding the Area of a Composite Shape:

A photographer sells three sizes of frames with borders. For each size, find the area of:

A shape with a width of 13.5cm and a length of 16.5cm and has a 20mm border.

The questions are:

1. The photograph without the frame border.
2. The photograph and frame border together.
3. The frame border.

If anyone knows how to work it and could tell me it would be much appreciate.

Thanks Jasmine

(edited 8 years ago)

Reply 1

aadil10

Original post by mizliljaz

I have a BKSB question from the workbooks for Perimeter And Area that I don't understand how to work out.

Finding the Area of a Composite Shape

A photographer sells three sizes of frames with borders. For each size, find the area of:

A shape with a width of 13.5cm and a length of 16.5cm and has a 20mm border.

The questions are:

1. The photograph without the frame border.
2. The photograph and frame border together.
3. The frame border.

If anyone knows how to work it and could tell me it would be much appreciate.

Thanks Jasmine

I'm assuming here that the border is included in the length and width measurements

1) Subtract the border twice from the length and width (as it's on top, bottom and both sides).
So 13.5-0.2-0.2=... and 16.5-0.2-0.2=...
then multiply to get area

2) Simply width x length

3) Answer (2) minus answer (1)