Answer:
√2(√3 - 1)/4
Step-by-step explanation:
To find an exact value for Cos75°, we use the compound angle formula. Since 75° = 45° + 30°, Cos75° = Cos(45° + 30°).
Using Cos(A + B) = CosACosB - SinASinB where A = 45° and B = 30°,
Cos75° = Cos(45° + 30°) = Cos45°Cos30° - Sin45°Sin30°
Now Cos45° = Sin45° = 1/√2 = √2/2, Cos30° = √3/2 and Sin30° = 1/2.
Substituting these values into the above equation, we have
Cos75° = Cos(45° + 30°)
= Cos45°Cos30° - Sin45°Sin30°
= √2/2 × √3/2 - √2/2 × 1/2
= √6/4 -√2/4
= √2(√3 - 1)/4
<em>Good luck, you'll need it :)</em>
Answer: 32 meters
Explanation: The 4 meter pole casts a shadow of 5 meters. The towers unknown height casts a shadow of 40 meters. Now isolate the shadows. 5 and 40. 40 divided by 5 is 8, so 4 times 8 is 32.
You don't say whether this is a right triangle or not.
Assuming it is a right triangle, then we use the Pythagorean Theorem to determine the length of the hypotenuse:
(hypo) = (length of third side) = √(12^2 + 4^2) = √(144+16) = √160 = 4√10.
This is approx. 12.65 inches. Since this does not match any of the possible answer choices, we'll have to take a different approach to answering this question.
Given that 2 sides of the given triangle are 12 and 4 inches, respectively, we see that the 3rd side has to be longer than 8 inches; otherwise we'd have three line segments on the same line, not forming a triangle.
By this reasoning, 9 inches is the only possible answer that could be correct. With sides 12, 9 and 4 inches, the triangle would be obtuse and appear quite flat, but not be part of a straight line as with a third side of 8.
You first identify what supplementary angles are,angles that add up to 180.
5x+2+8x+9=180
17x+11=180-11
17x=169
x=169divided by 17
x=9.9411
x=10 when rounded into the next value
8x*10=80+989
