Answer: 138.16 in²
Step-by-step explanation:
You need to use this formula to calculate the surface area of the cone:
[tex]SA = \pi r^2 + \pi rl[/tex]
Where "r" is the radius, "h" is the height and "l" is the slant height.
To find the height you need to use the Pythagorean Theorem:
[tex]a^2=b^2+c^2[/tex]
Where "a" is the hypotenuse and "b" and "c" are the legs of the triangle.
In this case:
[tex]a=l=7in\\\\b=r=\frac{8in}{2}=4in\\\\c=h[/tex]
("r" is the radius and "h" is the height and "l" is the slant height.)
You need to find "h". Then, solving for "h", you get:
[tex]h=\sqrt{(7in)^2-(4in)^2}\\h=5.74in[/tex]
Then, substituting values into the formula, you get:
[tex]SA = (3.14)(4in)^2 + (3.14) (4in)(7in)=138.16in^2[/tex]
