Answer:
Step-by-step explanation:
If arccos (√3 / 2) = β, then cos β = adjacent side / hypotenuse = √3 / 2. This tells us immediately that the adjacent side length is √3 and the hypotenuse is 2. Via the Pythagorean Theorem, we know that the third side is 1.
This information rules out the 1st and 3rd answer choices.
Because cos 30° = adj / hyp = √3 / 2, we can conclude that the correct answer is the 4th one: 30°, 60°, 90°
The answer is 6:15, but if u need to simplify the answer would be 2:5.
Here is a list of the odd number paired
1+3, 1+5, !+7, and !+9 (there are 4 unique sums - 4, 6,8 and 10)
3+5, 3+7, 3+9 (notice I did not pair 3 with 1 and the the only new sum is 12)
5+7, 5+9 (the only new sum is 14)
7+9 (16 is a new sum)
The sums (no repeats) are 4,6,8,10,12,14 and 16 for a total of seven numbers.