Answer:
okay...... where is the question
Paper he needs = total surface area
So to break it down into 2D shapes, that prism has 2 2D triangles, and 3 2D rectangles of different sizes.
The triangles are the same size, since you have 2, just multiply 2 by the formula for the area of a triangle: 1/2(base)(height) which is 2x1/2(5)(12) = 60
Next you'll need the area of all the rectangles: length x width. which would be (5 x 5) + (13 x 5) + (12 x 5) = 150
So the total amount of wrapping paper he'd need is 150mi^2
5/8 * 15 = 9.375000 exactly. The closest number to 9 is 3, which is below 5. This means to round the number down to the number it is closer to. 9.375 is closer to 9 than any other number, so we round it down to 9. Since Cassidy has 10 feet of string, and she uses the same amount for each bracelet, we can assume that she has enough to make 15 bracelets, possibly even 16.
