Show the sizes of the other angles and the lengths of any
lines that are known
Mark the angles or sides you have to calculate.
Consider whether you need to create right triangles by
drawing extra lines. For example, divide an isosceles triangle
into two congruent right triangles.
Decide whether you will need Pythagoras theorem, sine, cosine
Check that your answer is reasonable. The hypotenuse is the
longest side in a right triangle.
Calculate the value of cos θ in the following
Use Pythagoras theorem to evaluate the length of PR.
Calculate the length of the side x, given that tan
θ = 0.4
Calculate the length of the side x, given that sin
θ = 0.6
Using Pythagoras theorem:
Solve Word Problems using Trigonometry
The following video shows how to use the trigonometric ratio,
tangent,to find the height of a balloon.
This video shows how to use the trigonometric ratio, sine, to
find the elevation gain of a hiker going up a slope.
A hiker is hiking up a 12 degrees slope. If he hikes at a constant
rate of 3 mph, how much altitude does he gain in 5 hours of
How to Use Cosine to Solve a Word Problem.
A ramp is pulled out of the back of truck. There is a 38 degrees
angle between the ramp and the pavement.If the distance from the
end of the ramp to to the back of the truck is 10 feet. How long
is the ramp?
The following video shows how to use trigonometric ratio, tangent,
to find the height of a building
The following video shows how to solve trigonometry word problems
Neil sees a rocket at an angle of elevation of 11 degrees. If Neil
is located at 5 miles from the rocket launch pad, how high is the
Trigonometry Word Problem,
Determining the Speed of a Boat
A balloon is hovering 800 ft above a lake. The balloon is observed
by the crew of a boat as they look upwards at an angle of 0f 20
degrees. 25 seconds later, the crew had to look at an angle of 65
degrees to see the balloon. How fast was the boat traveling?
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