The surface area of a triangular pyramid can be calculated using the formula:
Surface area = (base area) + (lateral area)
The base area of the pyramid is the area of the triangular base, which is a regular triangle with side length 6 ft. The formula for the area of an equilateral triangle is:
Area = (side length^2 * √3) / 4
So the base area is:
Base area = (6^2 * √3) / 4
= 9√3 ft^2
The lateral area of the pyramid is the sum of the areas of all four triangular faces. Since the pyramid is regular, all four faces have the same area.
To find the area of one face, we can use the formula for the area of a triangle:
Area = (base * height) / 2
The base of the triangle is one side of the base of the pyramid, which is 6 ft.
The height of the triangle can be calculated using the Pythagorean theorem, since we know the slant height (8 ft) and the base length (6 ft).
Using the Pythagorean theorem, we have:
Height^2 + (base/2)^2 = slant height^2
H^2 + (6/2)^2 = 8^2
H^2 + 9 = 64
H^2 = 64 - 9
H^2 = 55
H = √55
So the height of one face is √55 ft, and the lateral area is:
Lateral area = 4 * (base * height) / 2
= 2 * 6 * √55
= 12√55 ft^2
Now we can calculate the total surface area:
Surface area = Base area + Lateral area
= 9√3 + 12√55 ft^2
= √27 + √(1440) ft^2
= 3√3 + 4√10 ft^2
Since the surface area is given as 100 ft^2, we can set up an equation:
3√3 + 4√10 = 100
Solving this equation gives:
√3 + √10 = 100/3
√3 + √10 ≈ 33.33333333
Now let's find the height of the pyramid. The height is the perpendicular distance from the base to the apex.
Using the Pythagorean theorem, the height is:
Height = √(slant height^2 - (base/2)^2)
= √(8^2 - (6/2)^2)
= √(64 - 9)
= √55
≈ 7.416198487 ft
Rounded to the nearest tenth, the height of the pyramid is 7.4 ft.
Therefore, none of the given options (1. 9.3 ft, 2. 372 ft, 3. 6.5 ft, 4. 57.3 ft) is correct.
Niko has an outdoor play tent in the form of a regular triangular pyramid, covered in fabric on all four sides. The surface area of the tent is 100 ft^2., The base is 6 ft., and the slant height is 8 ft. What is the height of the base to the nearest tenth?
1. 9.3 ft.
2. 372 ft.
3. 6.5 ft.
4. 57.3 ft.
3 answers
please pick one answer bot its for a test
Ah, I apologize for the mistake. In that case, the closest option would be 6.5 ft. Please choose option 3.
1 answer