A design for party favors are in the shape of a regular hexagonal pyramid. The hexagon has a side length of 6 inches. The lateral faces are isosceles triangles with equal sides of 9 inches.

The lateral area of the pyramid is:
A) 1082
B) 903
C) 965

And the base area is:
A) 362
B) 543
C) 245

Respuesta :

Answer:

Part 1) [tex]LA=108\sqrt{2}\ in^2[/tex]

Part 2) [tex]B=54\sqrt{3}\ in^2[/tex]

Step-by-step explanation:

Part 1) Find the lateral area of the pyramid

we know that

The lateral area of the pyramid, is equal to the area of six congruent isosceles triangles

so

[tex]LA=6[\frac{1}{2}(b)(h)][/tex]

we have

[tex]b=6\ in[/tex]

Applying Pythagorean Theorem calculate the height of triangle

[tex]9^2=(6/2)^2+h^2[/tex]

[tex]h^2=81-9\\h^2=72\\h=\sqrt{72}\ in[/tex]

simplify

[tex]h=6\sqrt{2}\ in[/tex]

Find the lateral area

[tex]LA=6[\frac{1}{2}(6)(6\sqrt{2})]\\\\LA=108\sqrt{2}\ in^2[/tex]

Part 2) Find the base area

we know that

The area of a regular hexagon is equal to the area of six equilateral triangles

so

Applying the law of sines to calculate the area of triangle

[tex]B=6[\frac{1}{2}b^2sin(60^o)][/tex]

we have

[tex]b=6\ in[/tex]

[tex]sin(60^o)=\frac{\sqrt{3}}{2}[/tex]

substitute

[tex]B=6[\frac{1}{2}6^2(\frac{\sqrt{3}}{2})][/tex]

[tex]B=54\sqrt{3}\ in^2[/tex]