Answers:
- a) 693 sq cm (approximate)
- b) 48 sq cm (exact)
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Explanation:
Part (a)
A regular triangular pyramid, aka regular tetrahedron, has all four triangles that are identical copies of one another. They are congruent triangles. This will apply to part (b) as well.
To find the area of one of the triangles, we'll use the formula
A = 0.25*sqrt(3)*x^2
where x is the side length. This formula applies to equilateral triangles only.
In this case, x = 20, so
A = 0.25*sqrt(3)*x^2
A = 0.25*sqrt(3)*20^2
A = 173.20508 approximately
That's the area of one triangle, but there are four total, so the entire area is about 4*173.20508 = 692.82032 which rounds to 693 sq cm.
The units "sq cm" can be written as "cm^2".
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Part (b)
We'll use the same idea as part (a). But the formula to find the area of one triangle is much simpler.
The area of one of the triangles is A = 0.5*base*height = 0.5*6*4 = 12 sq cm.
So the area of all four triangles combined is 4*12 = 48 sq cm
This area is exact.
The area of each 2D flat net corresponds exactly to the surface area of each 3D pyramid. This is because we can cut the figure out and fold along the lines to form the 3D shapes.
Answer:
i dont got the answer but u can download a pic
calculator so this picture will give u answers.
Answer:
390
Step-by-step explanation:
assuming the sample is representative
65 took survey = 10 percent of sample (650)
39 said yes
total = 39 x 10 = 390
Answer:
Step-by-step explanation:
The best first step to solve this is to just subtract 5/3 from both sides so it is easier to simplify.
(2^2)(10)=40
Hope this helps!
