Answer:
(A)[tex]6in^2[/tex]
Step-by-step 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=[tex]\sqrt{(3-7)^2+(10-7)^2}[/tex]
AB=[tex]\sqrt{16+9}[/tex]
AB=[tex]5in[/tex]
Also, BC=[tex]\sqrt{(3-3)^2+(10-7)^2}[/tex]
BC=[tex]\sqrt{0+9}[/tex]
BC=[tex]3in[/tex]
and CA=[tex]\sqrt{(3-7)^2+(7-7)^2}[/tex]
CA=[tex]\sqrt{16}[/tex]
CA=[tex]4in[/tex]
Now, area of triangle=[tex]\frac{1}{2}{\times}BC{\times}CA[/tex]
=[tex]\frac{1}{2}{\times}3{\times}4[/tex]
=[tex]6in^2[/tex]
Thus, [tex]6in^2[/tex]of fabric she will need if each unit on the grid is one inch.
