Step 1: Read, understand, and interpret the problem. What information is presented? Interactive popup. Assistance may be required. Check Your Answer The dimensions of the room are given. Wallpaper costs $1.75 per square foot. What is the problem asking me to find? Interactive popup. Assistance may be required. Check Your Answer We need to find the total cost of the wallpaper. To do so, we must first find the area of the wall. What information may be extra information that I do not need? Interactive popup. Assistance may be required. Check Your Answer There may be dimensions that are not necessary, depending on how we partition the wall. For example, the sides marked 5 feet in length may not be important for our calculations.

Step 2: Make a plan. Draw a picture.

Step 3: Implement your plan. What formulas do I need? Interactive popup. Assistance may be required. Check Your Answer Area of a Rectangle: A = bh Area of Trapezoid: A = 1 over 2 1 2 (b1 + b2)h What information can I interpret from the diagram, table, or other given information? Interactive popup. Assistance may be required. Check Your Answer I will need to partition the wall into two pieces: a rectangle and a trapezoid: Solve the problem. Interactive popup. Assistance may be required. Check Your Answer Answer: $189 Area of the rectangle: bh = (10 feet)(8 feet) = 80 square feet Area of Trapezoid: A = 1 over 2 1 2 (b1 + b2)h = 1 over 2 1 2 (10 feet + 4 feet) = 1 over 2 1 2 (14 feet)(4 feet) A = (7 feet)(4 feet) = 28 square feet Total Area = Area of Rectangle + Area of Trapezoid Total Area = 80 square feet + 28 square feet = 108 square feet

Step 4: Evaluate your answer. Does my answer make sense? Interactive popup. Assistance may be required. Check Your Answer Yes. The wall is 10 feet wide and 12 feet tall with two corners at the top missing. Therefore, the area should be slightly less than 10 × 12 = 120 square feet, and 108 square feet makes sense for the area. The cost is just under $2 per square foot, and the area is about 100 square feet. $2 × 100 = $200, so my total cost should be about $200, and $189 is about $200. Did I answer the question that was asked? Interactive popup. Assistance may be required. Check Your Answer Yes. I was asked to determine the cost, not just the area. Are my units correct? Interactive popup. Assistance may be required. Check Your Answer Yes. The units for cost are dollars, not square feet.

Step 1: Read, understand, and interpret the problem. What information is presented? Interactive popup. Assistance may be required. Check Your Answer The dimensions of the house are given. The roof will cost $2.75 per square foot. What is the problem asking me to find? Interactive popup. Assistance may be required. Check Your Answer We need to find the total cost of the roof. To do so, we must first find the combined area of the roof, which is composed of 2 rectangles. What information may be extra information that I do not need? Interactive popup. Assistance may be required. Check Your Answer The depth of the house, 25 feet, is information presented that is not necessary for the solution to this problem.

Step 2: Make a plan. Draw a picture.

Step 3: Implement your plan. What formulas do I need? Interactive popup. Assistance may be required. Check Your Answer Area of a Rectangle: bh What information can I interpret from the diagram, table, or other given information? Interactive popup. Assistance may be required. Check Your Answer The roof is shaped like 2 congruent rectangles, each with a base of 50 feet and a height of 14 feet. Solve the problem. Interactive popup. Assistance may be required. Check Your Answer Answer: $3,850 Area of one rectangle: A = bh = (50 feet)(14 feet) = 700 square feet Total Area = 2 × Area of Rectangle Total Area = 2 × 700 square feet = 1,400 square feet

Step 4: Evaluate your answer. Does my answer make sense? Interactive popup. Assistance may be required. Check Your Answer Yes. Each side of the roof is 50 feet long and about 15 feet wide. 50 × 15 = 750, and 750 × 2 = 1,500. The cost per square foot rounds to $3, so 1,500 × $3 = $4,500, which is a good estimate for the cost of the roof. Did I answer the question that was asked? Interactive popup. Assistance may be required. Check Your Answer Yes. I was asked to determine the cost, not just the area. Are my units correct? Interactive popup. Assistance may be required. Check Your Answer Yes. The units for cost are dollars, not square feet.