Trigonometry (SOH CAH TOA)

What you'll learn

1. 1

   Imagine a ladder leaning against a wall. The ladder is the longest side — we call it the hypotenuse.

2. 2

   In a right-angled triangle, which side is always the longest?

3. 3

   Here's a right-angled triangle. The angle is marked with θ. Can you see the three sides?

4. 4

   SOH CAH TOA helps us remember which ratio to use. SOH means Sine = Opposite ÷ Hypotenuse.

5. 5

   Let's find the missing side in this triangle using SOH CAH TOA.

6. 6

   Drag the labels to match the sides of this triangle with SOH CAH TOA.

7. 7

   Which ratio would you use if you know the opposite and hypotenuse?

8. 8

   In a right-angled triangle with angle 30°, opposite side = 3 cm, what is the hypotenuse? (Use sin 30° = 0.5)