Question

A seamstress is making a decorative pillow and wants to cover both sides of the pillow with special fabric. The pillow is in the shape of a triangle with vertices (7, 7) (10, 3) (7, 3). How many square inches of fabric will she need if each unit on the grid is one inch?

6 in2
7 in2
15 in2
12 in2

Answer 1

6in^2

Explanation:

Answer 2

(A)
`6in^2`

Explanation:

It is given that the pillow is in the shape of a triangle with vertices (7, 7) (10, 3) (7, 3).

Let A=(7,7), B=(10,3) and C=(7,3), then using the distance formula, we get

AB=
`√((3-7)^2+(10-7)^2)`

AB=
`√(16+9)`

AB=
`5in`

Also, BC=
`√((3-3)^2+(10-7)^2)`

BC=
`√(0+9)`

BC=
`3in`

and CA=
`√((3-7)^2+(7-7)^2)`

CA=
`√(16)`

CA=
`4in`

Now, area of triangle=
`(1)/(2){*}BC{*}CA`

=
`(1)/(2){*}3{*}4`

=
`6in^2`

Thus,
`6in^2`of fabric she will need if each unit on the grid is one inch.