Answer:
Square inches of fabric required = 12
Step-by-step explanation:
Distance from (a,b) to (c,d) [tex]=\sqrt{(c-a)^2+(d-b)^2}[/tex].
Distance from (7, 7) to (10, 3) [tex]=\sqrt{(10-7)^2+(3-7)^2}=5\texttt{ inch}[/tex]
Distance from (10, 3) to (7, 3) [tex]=\sqrt{(7-10)^2+(3-3)^2}=3\texttt{ inch}[/tex]
Distance from (7, 3) to (7, 7) [tex]=\sqrt{(7-7)^2+(7-3)^2}=4\texttt{ inch}[/tex]
Area of triangle [tex]=\sqrt{s(s-a)(s-b)(s-c)}[/tex], where [tex]s=\frac{a+b+c}{2}[/tex]
Here a = 5, b = 3 and c = 4
[tex]s=\frac{5+3+4}{2}=6[/tex]
Area of triangle [tex]=\sqrt{6(6-5)(6-3)(6-4)}=12\texttt{ square inch}[/tex]
Area of pillow = 2 x Area of triangle = 2 x 6 = 12 square inch
Square inches of fabric required = 12
