• Quick retrieval from earlier learning (Label hypotenuse, opposite and adjacent sides). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. In triangle ZQP, the right angle is at Q. Using angle Z, which side is the opposite? (ZQ / ZP / QP) → QPPrompt: Sketch the triangle and mark the right angle.
2. In triangle NRQ, the right angle is at R. Using angle N, which side is the adjacent? (NR / NQ / RQ) → NRPrompt: Sketch the triangle and mark the right angle.
3. In triangle MPX, the right angle is at P. Using angle M, which side is the adjacent? (MX / MP / PX) → MPPrompt: Sketch the triangle and mark the right angle.

• Show a ramp or a ladder against a wall and ask how steep it is.
• Share the objective: Choose sine, cosine or tangent for a problem. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: In a right triangle you know angle θ and the hypotenuse. You want the adjacent side. Which ratio should you use?
• Step 1: cos
• Answer: cos
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. In a right triangle you know angle θ and the hypotenuse. You want the opposite side. Which ratio should you use? (sin / cos / tan) → sinPrompt: SOH CAH TOA: which ratio links the two sides involved?
2. A 16 m ladder leans against a wall at 30° to the ground. To find how high up the wall it reaches, which ratio do you use with the 30° angle? (sin / cos / tan) → sinPrompt: The ladder is the hypotenuse.

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. In a right triangle you know angle θ and the adjacent side. You want the hypotenuse. Which ratio should you use? (sin / cos / tan) → cosPrompt: SOH CAH TOA: which ratio links the two sides involved?
2. A 12 m ladder leans against a wall at 68° to the ground. To find how high up the wall it reaches, which ratio do you use with the 68° angle? (sin / cos / tan) → sinPrompt: The ladder is the hypotenuse.

Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-10.