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Warm Up: a) Identify the reciprocal ratios for BAT. b) Solve for angle B. Unit 5: Trigonometry Day 2: Sine and Cosine Laws Today we will.....Review the Sine and Cosine Law formulas, solve triangles using the sine and cosine laws and solve word problems using the sine and cosine laws The Primary Trig Ratios (SOH-CAH-TOA) only work when we have a _____________________________ TRIANGLE. When the triangle _______ _______ contain a right-angle we use The Sine Law or The Cosine Law. The Sine Law Used when: we know two _________ and one corresponding _____________ we know two _____________ and one ___________ The Cosine Law Used when: we know three ____________ and no ___________ we know two sides and their _______________ angle Example 1: In ΔRST, S = 40ο, T = 21ο and r = 46 cm. Find t, to the nearest centimetre. Example 2: In ΔPQR, P = 105.2ο, p = 23.2 cm and r = 18.5 cm. Solve the triangle. Example 3: Solve the following triangle. Round each angle to the nearest tenth of a degree. Example 4: Find the length of CD, to the nearest tenth of a metre.