Answer:
18√91 +54√3
Step-by-step explanation:
Name the point at the top of the pyramid "A", the point at the left front corner "B", and the one in the center of the hexagonal base "C". Then right triangle ABC is shown. The "base" BC of that triangle is the same measure as the front edge (6), because the diameter of a regular hexagon is equal to twice the side length.
Using the Pythagorean theorem, we can find the face edge length to be ...
AB^2 = BC^2 +AC^2
AB^2 = 6^2 +8^2 = 100
AB = √100 = 10
If we call the midpoint of the front edge "D", then we need to find the length of AD in order to determine the face area. Again, we can use the Pythagorean theorem.
AB^2 = BD^2 +AD^2
AD^2 = AB^2 -BD^2 = 10^2 -3^2 = 91
AD = √91
The area of one of the 6 lateral faces is ...
A = (1/2)bh = (1/2)(6)√91 = 3√91
The area of one of the 6 equilateral triangles that make up the base is ...
A = (√3)/4·s^2 = (√3)/4(6^2) = 9√3
Then the total area of the pyramid is ...
total area = 6 × (face area + partial base area)
= 6(3√91 +9√3)
total area = 18√91 +54√3
