Question

FIND THE SURFACE AREA OF THE FOLLOWING SHAPES! Round to the nearest tenth IF NECESSARY!

Answer 1

1.
`360cm^(2)`

2.
`A=1657.9mi^(2)`

3.
`A=215.8ft^(2)`

4.
`204ft^(2)`

Explanation:

1. Find the area of the base. 10×10=100. Now, find the area of one of the triangles. 5×13=65. Multiply 65 by 4. Now, add this number to 100. 100+260=
`360cm^(2)`

2. Divide the diameter by 2 to get the radius. r=12. h=10.
`A=2\pi rh+2\pi r^(2)`.
`A=2(3.14)(12)(10)+2(3.14)(12)^(2)`.
`A=6.28(12)(10)+2(3.14)(12)^(2)`.
`A=75.36(10)+2(3.14)(12)^(2)`.
`A=753.6+2(3.14)(12)^(2)`.
`A=753.6+6.28(12)^(2)`.
`A=753.6+(6.28)(144)`.
`A=753.6+904.32`.
`A=1657.9mi^(2)`

3.
`A=\pi r(r+\sqrt{h^(2)+r^(2) })`. r=4. h=12.6.
`A=(3.14)(4)(4+\sqrt{12.6^(2) +4^(2) } )`.
`A=12.56(4+\sqrt{12.56^(2)+4^(2) } )`.
`A=12.56(4+\sqrt{157.756 +4^(2) } )`.
`A=12.56(4+√(157.7536+16) )`.
`A=12.56(4+√(173.7536) )`.
`A=12.56(4+13.1815)`.
`A=12.56(17.1815)`.
`A=215.8ft^(2)`

4. Find the area of the base. 9×4=36. Multiply this by two to get the base and the top. This is 72. Now, find the front side area. 9×3=27. Multiply this by two to get the front and back sides. This is 54. Now, find the area of the left side face. 4×3=12. Multiply this by 2 to get both sides. This is 24. Add 72+54+24=
`204 ft^(2)`