Answer:
Part A- yes, because all 3 sides are Equal (each side is 5)
Part B- yes, each rectangle has the dimensions 12*5
Part C- yes- since the sides are 5 and 12 you can determine that the diagonal is 13, using they Pythagorean theorem 
- true statement, so the lateral sides are rectangles, because the corners are 90
Part D-
(it is a 45-45-90 triangle- so the hypotenuse is the side length times 
Part E- the diagonal face as the largest area- dimensions are 
the area would be 
Step-by-step explanation:
Answer: The markup on the T-shirts is $ 13.50.
Step-by-step explanation:
- Markup is the difference between the selling price of a product and cost price.
Given : The cost price of each t-shirt = $1.50
The selling price of each t-shirt = $15
Then ,the markup on the T-shirts = (Selling price of each t-shirt) -( Cost price of each t-shirt)
i.e. The markup on the T-shirts = $15- $1.50= $ 13.50
Hence, the markup on the T-shirts is $ 13.50.