Answers in bold.
- 1. angle of inclination = 10 degrees
- 2a. Height = 80 meters
- 2b. Horizontal distance = 157 meters
Each result is approximate, and rounded to the nearest whole number. If the rounding instructions for problem 2 are different (say to the nearest tenth), then be sure to follow those instructions. The diagrams are provided below.
==========================================================
Step-by-step explanation:
Problem 1
Draw a right triangle with vertical leg 0.7 meters and hypotenuse 4.2 meters. Refer to figure 1 shown below. The angle theta (symbol
) is opposite the vertical side. It's the angle of inclination, aka angle of elevation.
sin(angle) = opposite/hypotenuse
sin(theta) = 0.7/4.2
sin(theta) = 7/42
sin(theta) = 1/6
theta = arcsin(1/6)
theta = 9.594068 approximately
theta = 10 degrees approximately
Make sure your calculator is in degree mode. The notation arcsin, aka arcsine, is the same as inverse sine. It has the notation
on many calculators.
-------------------------------
Problem 2a
Refer to figure 2 shown below.
sin(angle) = opposite/hypotenuse
sin(27) = y/176
y = 176*sin(27)
y = 79.9023279541602
y = 80 meters
The kite is about 80 meters off the ground.
Side note: 80 meters = 262.467 feet approximately
-------------------------------
Problem 2b
Refer to figure 2 shown below.
cos(angle) = adjacent/hypotenuse
cos(27) = x/176
x = 176*cos(27)
x = 156.817148257152
x = 157 meters
The kite is horizontally about 157 meters away from the person.
157 meters = 515.092 feet approximately
An alternate approach to finding x is through the pythagorean theorem. This requires section 2a done first.
a^2+b^2 = c^2
x^2+y^2 = 176^2
x = sqrt(176^2-y^2)
x = sqrt(176^2-79.9023279541602^2)
x = 156.817148257152
x = 157 meters
Notice we used the value of y, which was computed in section 2a. This means the pythagorean theorem option is not available for section 2a because we don't have enough info about the sides.
Once we know two sides of a right triangle, we can use the pythagorean theorem. In other words, if you did section 2b first, then you could use the pythagorean theorem for section 2a.