a house with a rectangular floor plan measuring 22m by 8m has a roof that has four faces. each of the two larger faces has the shape of an isocles trapezium, and they meet in a 14m long ridge at the top. on the ends of the house there are two faces - each one is shaped like an isocles triangle. jerry, a builder's apprentice, looks at the plans and says the area of the roof will be 176m2. explain why jerry is wrong.
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Good old Jerry did it again! I told you NEVER to let him calculate the amount of materials needed on any job. This time he figured the AREA of the BUILDING, not the ROOF. These are two different things as the roof consists of triangles which have a larger area than a flat rectangle does. The correct method to solve this problem is to calculate the Area of four right triangles, A=ab/2 that comprise the two ends of the roof, each with a base of 4 meters and a height of 4 meters, giving a hypotenuse of: (4 x 4)/2 = 8 sq. meters x 4 = 32 sq. meters, Total.
The formula for the two large trapezoids is: A = [H (a + b)] / 2 and they measure 22 by 14 by 8 meters. Each of these equals have an area of 1,743.28 sq meters for a total of 3,486.56 sq. meters. Add both of these together: 3,486.56 + 32 = 3,518.56 sq meters total roof area.
You better have a talk with Jerry before I fire the dude.
The formula for the two large trapezoids is: A = [H (a + b)] / 2 and they measure 22 by 14 by 8 meters. Each of these equals have an area of 1,743.28 sq meters for a total of 3,486.56 sq. meters. Add both of these together: 3,486.56 + 32 = 3,518.56 sq meters total roof area.
You better have a talk with Jerry before I fire the dude.
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Pay attention in class