A right triangle is formed by squares made up of Identical square blocks as shown

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

There are 48 blue cards total

The only number less than 8 that can equal 12 would be 6, 36 is the dividend