The standard deviation is lower for each group than it is for the groups combined.
Answer: d. The helicopter rotor will spin 36,000 times in 1 hour
Step-by-step explanation:
Option A is wrong because in 40 minutes the rotor will spin:
= 40 * 600
= 24,000 times
Option B is wrong because we cannot know the number of times the rotor will spin before being lifted off of the ground with the details given.
Option C is wrong because in 3 hours the rotor will spin:
= 600 * 3 * 60 minutes
= 108,000 times
Option D is correct because in 1 hour the rotor will spin:
= 600 * 1 * 60 mins
= 36,000 times
9514 1404 393
Answer:
470.16 cm²
Step-by-step explanation:
The apothem of the base is used for two purposes: to find the area of the base, and to find the slant height of each face.
The apothem of the base for side length s is ...
s/2 = a·tan(π/8)
a = s/(2·tan(π/8)) ≈ 7.24 cm
The slant height of a triangular face is found using the Pythagorean theorem. The apothem of the base and the height are legs of the right triangle whose hypotenuse is the slant height. For slant height x, we have ...
x² = 10² + a² = 100 +52.46
x ≈ √152.46 ≈ 12.35
__
The area of the 8 triangular faces will be ...
A = 1/2Px . . . . where P is the perimeter of the pyramid
The area of the base will be ...
A = 1/2Pa
So, the total surface area is ...
A = 1/2P(a + x) = (1/2)(8)(6 cm)(7.24 +12.35 cm) ≈ 470.16 cm²
<span>The first step you need to do is to rewrite
x+y=3
as y=3-x
</span><span>Now we can replace the y in the equation with our newfound value for y, which is
y=3-x.
So lets write it now like this
Q=x^2+2(3-y)^2
=x^2+18-12x+2x^2
=3x^2+18-12x
</span>Hope this helps
