# Geometry-Trigonometry

• 23 April 2018
• Posted by: Simone Tingling
• Number of views: 5239
Students’ age range: 14-16
Topic: Geometry-Trigonometry - Subtopic Sine - Content Summary Trigonometry at its simplest level is a branch of Mathematics that deals with the length of sides and angles in right angled triangles. The

Description: Revision: students will be asked the following questions; a. Draw a right angled triangle; label the hypotenuse and put in the right angle symbol. b. Give each angle and sides a name (angles A, B, C and sides a, b, c). c. Draw an isosceles triangle with the sides measuring the following lengths; 4cm, 4cm and 8cm. students will draw a perpendicular bisector from the apex of a triangle to the base. Students will correctly place in the two right angles. Step1: Students will draw a right angled triangle and label the sides. They will write on the hypotenuse, adjacent and opposite sides. Students and teacher will discuss what makes a side the opposite. Students will participate in class activity to identify the side based on the angle in question. Step2: 1. Teacher will introduce students to the sine ratio. Students will find the ratio on their calculator. 2. Students will attempt to fine the sine of given angles using their calculators, eg 30º, 45º, 75º, etc. 3. Students will use their calculators to find angles using sine inverse of numbers, eg 0.5, 0.98, 0.45, etc. 4. Teacher will draw a right angle triangle on the board with a specific angle (30 degrees) and the hypotenuse measuring 20cm, student will be asked to locate the opposite side. 5. Teacher will introduce students to the formula for sine. Students will attempt to use the formula to find the length of the opposite side. Teacher will assist the students if they are having difficulty applying the formula. 6. Students and teacher will work a problem together. Students will ask any further questions that they have. 7. A question will be written on the board where the hypotenuse is the unknown. Students will attempt to use the formula to find the length of the hypotenuse. Teacher will assist the students if they are having difficulty applying the formula. 8. Students will be given another question to calculate the unknown angle. Students will attempt to find the size of angle using sine ratio and convert the answer to degrees using sine inverse. Teacher will assist the students if they are having difficulty applying the formula and converting from decimal to degrees (sign inverse) correctly. 9. Students will be presented with a real life question to apply the sine formula to; Question: Eddie needs a new stay wire on his sailboat to replace one that broke in a high wind. The mast on his sailboat is 4.5m tall, and the stay wire must make an angle of 60 degrees with the deck of the boat. What length of wire stay does he need? Students will sketch and label the diagram correctly. Assessment Students will: 1. Do independent practice problems from page572-574 exercise11a #2-5,17, 18, 24, 27 Mathematics A Complete Course Volume 1 by Raymond Toolsie, 2. Living Mathematics for Jamaica Book 3 by I.S. Ferguson & P.Hill pp 206-207 exercise 14C # 1a,3,6, and 14D #1, 3 Evaluation2: Procedure: Revision: students will be asked the following questions; d. Draw a right angled triangle; label the hypotenuse and put in the right angle symbol. e. Given each angle and sides a name (angles A, B, C and sides a, b, c). f. Draw an isosceles triangle with the sides measuring the following lengths; 4cm, 4cm and 8cm. students will draw a perpendicular bisector from the apex of a triangle to the base. Students will correctly place in the two right angles. Step1: Students will draw a right angled triangle and label the sides. They will write on the hypotenuse, adjacent and opposite sides. Students and teacher will discuss what makes a side the opposite. Students will participate in class activity to identify the side based on the angle in question. Step2: 10. Teacher will introduce students to the sine ratio. Students will find the ratio on their calculator. 11. Students will attempt to fine the sine of given angles using their calculators, eg 30º, 45º, 75º, etc. 12. Students will use their calculators to find angles using sine inverse of numbers, eg 0.5, 0.98, 0.45, etc. 13. Teacher will draw a right angle triangle on the board with a specific angle (30 degrees) and the hypotenuse