Answer:

Step-by-step explanation:
Two angles are Complementary when they add up to 90°.
Therefore

<h3>
Answer: Choice B) 468 cm^2</h3>
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Explanation:
As the diagram shows, we have a triangular face with a base of b = 18 and height of h = 13. The area of this triangular face is:
A = 0.5*b*h
A = 0.5*18*13
A = 117 square cm or cm^2
This represents the area of one face, but there are 4 identical copies of this triangular face assuming this tetrahedron is a regular polyhedron. So we have a total surface area of 4*117 = 468 cm^2 which points us to choice B
This is the amount of paint you'll need to cover the outer surface of the pyramid, or you can think of it as the amount of wrapping paper needed. This assumes there are no gaps or overlaps.
Answer:
Check photo
Step-by-step explanation:
It’s order of operations it’s really easy
P- parentheses
E-exponents
M- multiply
D- divide
A- addition
S- subtraction
Do the problems in that order and u will get it answer
The sum of the interior angles of a triangle is always 180 degrees. Thus,
the sum of 31, x+4 and 3x+9 must be 180.
31 + x + 4 + 3x + 9 = 180, or 44 + 4x = 180
While it's not necessary, y ou could reduce this equation before solving for x:
11 + x = 45. Then x = 34 degrees.
The three angles are then:
31
34+4 = 38
3(34) + 9 = 111
Check: show that 31+38+111 = 180 (degrees)