Question

What are the surface areas of those ?

Answer 1

7)
`SA=13.8 yd^(2)`. 8)
`SA=96yd^(2)`

Explanation:

7)

Here we have two different types of faces.Bottom face and side faces which are equivalent.

To calculate the area of a trinagle we have the formula of area to be

`A=(1)/(2)ab`

where a is the height of the triangle and b is the base of the triangle.

here let us first calculate the area of the bottom face,

`a1=(1)/(2)*2.6*3`

`a1=3.9yd^(2)`

now for the top faces which are similar, areas would be

`a2=(1)/(2)*2.2*3`

`3*a2=9.9yd^(2)`

Hence the total area is

`9.9+3.9=13.8 yd^(2)`

8)

As we have seen in the above question area for a traingle would be

`A=(1)/(2)ah` and for rectangle would be
`lb` where l and b are the lengths and breaths of the rectangle.

Area of traingles would be ,

`A1=(1)/(2)*3*4+ (1)/(2)*3*4`

`A1=12`

Area of rectangles would be,

`A2=7*4+7*5+7*3`

`A2=84`

Hence the total area is

`A=96`