What is the total cost if the shirt cost $40 and 20% off

You'd simply have to find 20% of $40. To find the percent of a number, you would change the percent into an actual decimal/number, and then multiply them both. So the percent would become 0.20.

40 × 0.20 = 8

So now you would subtract 8 from the cost of 40.

 40 - 8 = 32.

The shirt costs $32.

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's