SOHCAHTOA -Trigonometry

Trigonometry

SOHCAHTOA

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How to label a triangle

Hypotenuse- The longest sloping edge opposite the right angle.

Opposite- The side opposite the angle given.

Adjacent- The side that is adjacent to (next to) the angle given.

Practice questions

Answers

HYP

HYP

ADJ

OPP

OPP

ADJ

ADJ

ADJ

OPP

HYP

HYP

OPP

What is SOHCAHTOA?

SOHCAHTOA is an easy way to remember the 3 main trigonometric ratios: Sine (Sin), Cosine (Cos), and Tangent (Tan). Theta is an angle (not the right angle) of the triangle.

Is used to find the opposite or hypotenuse

Is used to find the adjacent or hypotenuse

Is used to find the opposite or the adjacent

Example Question 1:

Label sides of triangle that we have information about

Find the side labelled x.

Choose the trig ratio we need. The trigonomic function that involves the opposite and hypotenuse is sin.

Calculate the unknown side, either by rearranging the equation or using the SOHCAHTOA triangle.

Substitute the values from the triangle into the function

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Example Question 2:

Label sides of triangle that we have information about

Find the length of the side labelled x.. Give your answer to 2 d.p.

Choose the trig ratio we need. The trigonomic function that involves the adjacent and hypotenuse is cos.

Calculate the unknown side.

Substitute the values from the triangle into the function

Practice questions

6)

4)

5)

Answers

13.6m

10.8m

3.8cm

6)

4)

5)

8.5cm

138.8cm

6.6cm

Quiz - Fast Recall

Quiz - Fast Recall

Quiz - Fast Recall

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