Tell whether each triangle with the given side lengths is a right triangle.
1 answer:
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Part A
Since order matters, we use the nPr permutation formula
We use n = 12 and r = 8
There are a little under 20 million different permutations.
<h3>Answer: 19,958,400</h3>Side note: your teacher may not want you to type in the commas
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Part B
In this case, order doesn't matter. We could use the nCr combination formula like so.
We have a much smaller number compared to last time because order isn't important. Consider a group of 3 people {A,B,C} and this group is identical to {C,B,A}. This idea applies to groups of any number.
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Another way we can compute the answer is to use the result from part A.
Recall that:
nCr = (nPr)/(r!)
If we know the permutation value, we simply divide by r! to get the combination value. In this case, we divide by r! = 8! = 8*7*6*5*4*3*2*1 = 40,320
So,
Not only is this shortcut fairly handy, but it's also interesting to see how the concepts of combinations and permutations connect to one another.
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<h3>Answer: 495</h3>Green Line:
This is a horizontal line at x = 0, so it would be:
x ? 0
Since the shaded area is going to the left of 0 (this means x is negative):
x ≤ 0
Blue Line:
The shaded area is below the line, so:
y ≤ mx + b
When x = 0, y is -5.
y ≤ mx - 5
From each point, you go up 3 units, and to the right 4 units, so the slope is .
Answer:
The distance between the hands is √(3)cm ≈ 1.73cm.
Step-by-step explanation:
In a standard clock, the angle between every number is 30°, therefore the angle between 12 and 2 will be 30° x 2 = 60°.
Looking at the diagram, to find c we can make use of our cosine formula
c² = a² + b² –2abCos(C°)
a = 2, b = 1 and C° = 60°
Therefore we have:
c² = 2² + 1² –2 x 2 x 1 x cos(60°) =
c² = 4 + 1 – 4 x 0.5 =
c² = 5 – 2 =
c² = 3
c = √(3) ≈ 1.73
Therefore, the distance between the hands is √(3)cm ≈ 1.73cm.
