Tangent (25) = opp / adj = 42 / horizontal distance
horizontal distance = 42 / tangent (25)
horizontal distance = 42 / 0.46631
horizontal distance =
<span>
<span>
<span>
90.068838326435200
</span>
</span>
</span>
horizontal distance =
90.1 feet
Time taken to reach a person located 5m from the source is 0.2s
<u>Explanation:</u>
Given:
Frequency, f = 10Hz
Wavelength, λ = 2.5m
Distance, d = 5m
Time, t = ?
We know:
velocity = f X λ
v = 10 X 2.5
v = 25 m/s
We know:
Distance = speed X time
On substituting the value we get:
5 = 25 X t
t = 0.2 seconds
Therefore, time taken to reach a person located 5m from the source is 0.2s
Answer:
Part 1)
Bob's mistake was to have used the cosine instead of the sine
The measure of the missing angle is 
Part 2) The surface area of the pyramid is 
Step-by-step explanation:
Part 1)
Let
x----> the missing angle
we know that
In the right triangle o the figure
The sine of angle x is equal to divide the opposite side angle x to the hypotenuse of the right triangle


Bob's mistake was to have used the cosine instead of the sine
Part 2) we know that
The surface area of the square pyramid is equal to the area of the square base plus the area of its four lateral triangular faces
so
![SA=b^{2}+4[\frac{1}{2}(b)(h)]](https://tex.z-dn.net/?f=SA%3Db%5E%7B2%7D%2B4%5B%5Cfrac%7B1%7D%7B2%7D%28b%29%28h%29%5D)
where
b is the length side of the square
h is the height of the triangular lateral face
In this problem
-------> by an 45° angle
so



Find the value of b

Find the surface area
![SA=12^{2}+4[\frac{1}{2}(12)(6)]=288\ cm^{2}](https://tex.z-dn.net/?f=SA%3D12%5E%7B2%7D%2B4%5B%5Cfrac%7B1%7D%7B2%7D%2812%29%286%29%5D%3D288%5C%20cm%5E%7B2%7D)
Answer: pretty sure lily is right
Step-by-step explanation: