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Question 1 of 4
A ship has traveled 68 km northwest from point P with a true bearing of 319°T. How far west (xw) has it traveled?
Round your answer to one decimal place
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A true bearing is an angle measured clockwise from the True North around to the required direction.
First, find the value of θ below.
Notice that it is part of the given bearing, which also consists of 3 quadrants from the North line moving clockwise.
To find the value of θ, simply subtract the measure of the angles from the three quadrants, 270°, from the given bearing.
θ |
= |
319°−270° |
|
= |
49° |
To solve for xw, we can use the known values of the hypotenuse and θ=49°.
Use cos to find the value of xw.
cos49° |
= |
xwhypotenuse |
|
cos49° |
= |
xw68 |
|
cos49°×68 |
= |
(xw68)×68 |
Multiply both sides by 68 |
|
68cos49° |
= |
xw |
xw |
= |
68cos49° |
Using your calculator, 68cos49°=44.6.
Therefore, the speedboat is 44.6 km to the West.
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Question 2 of 4
A marathon runner runs 25.3 km at a true bearing of 129°T. Find how far east (xe) the runner has traveled from the starting point (S).
Round your answer to one decimal place
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A true bearing is an angle measured clockwise from the True North around to the required direction.
First, find the value of θ below.
Notice that it is part of the given bearing, which also consists of a right angle from the North line moving to the East line.
To find the value of θ, simply subtract the value of a right angle, 90°, from the given bearing.
θ |
= |
129°−90° |
|
= |
39° |
To solve for xe, we can use the known values of the hypotenuse and θ=39°.
Use cos to find the value of xe.
cos39° |
= |
xehypotenuse |
|
cos39° |
= |
xe25.3 |
|
cos39°×25.3 |
= |
(xe25.3)×25.3 |
Multiply both sides by 25.3 |
|
25.3cos39° |
= |
xe |
xe |
= |
25.3cos39° |
Using your calculator, 25.3cos39°=19.7.
Therefore, the runner runs 19.7 km to the East.
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Question 3 of 4
A ship sails on a bearing of 200°T towards P. If P is 80 nautical miles west from O, find how far the ship has sailed (x).
Round your answer to one decimal place
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A true bearing is an angle measured clockwise from the True North around to the required direction.
First, find the value of angle QOP.
Notice that adding angle QOP to the given bearing (200°) will cover 3 quadrants, which is equal to 270°
To find the value of angle QOP, simply subtract the value of the bearing from 270°.
∠QOP |
= |
270°−200° |
|
= |
70° |
To solve for x, we can use the known values of the line adjacent to angle QOP.
Use cos to find the value of x.
cos70° |
= |
adjacentx |
|
cos70° |
= |
80x |
|
cos70°×x |
= |
(80x)×x |
Multiply both sides by x |
|
xcos70° |
= |
80 |
|
xcos70°÷cos70° |
= |
80÷cos70° |
Divide both sides by cos70° |
x |
= |
80cos70° |
Using your calculator, 80cos70°=233.9.
Therefore, the boat traveled 233.9 nautical miles in total.
233.9 nautical miles
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Question 4 of 4
Bianca leaves her home and cycles due North for 12 km, then 7 km due West to go to the gym. How far is the gym from her home (x)?
Round your answer to one decimal place
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Use the Pythagoras’ Theorem to solve for the distance (x).
a |
= |
x |
b |
= |
12 km |
c |
= |
7 km |
a2 |
= |
b2+c2 |
x2 |
= |
122+72 |
Substitute known values |
√x2 |
= |
√144+49 |
Get the square root of both sides |
x |
= |
√193 |
x |
= |
13.9 km |
Rounded to one decimal place |