# Drawing Triangles 1. Using a Protractor 2. Select SAS triangles

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Drawing Triangles 1. Using a Protractor 2. Select SAS triangles
MTH 3.16a 1. Using a Protractor 2. Select SAS triangles 3. Select ASA triangles 4. Select SSS triangles 31-Mar-17 Created by Mr. Lafferty

(SAS) Starter Questions
Q1. Convert the percentages to fractions. (a) 30% (b) 60% Q2. Write down all the factors of 16. Q3. Calculate the missing angles. 80o Q4. Round the following to 1 decimal place. (a) 4.549 (b) 6.551 31-Mar-17 Created by Mr. Lafferty

A 180o Protractor Outside scale from o to 180o going in a clockwise direction. Inside scale from o to 180o going in an anti-clockwise direction. 31-Mar-17

You need to be able to measure an angle to the nearest degree
You need to be able to measure an angle to the nearest degree. To help you do this you should always: 1. Look directly down onto the cross point. 2. Always use the protractor in a horizontal manner as shown below. 31-Mar-17

Measuring Angles with a 180o Protractor
2 0 on the inside so use inside scale 67o 0 on the outside so use outside scale 31-Mar-17

Measuring Angles with a 180o Protractor 120o
3 Measuring Angles with a 180o Protractor 120o 4 0 on the inside so use inside scale 135o 0 on the outside so use outside scale 31-Mar-17

Drawing SAS Triangles ‘We are learning to construct a triangle given
Aim of the Lesson ‘We are learning to construct a triangle given the length of two sides and the included angle’ 31-Mar-17 Created by Mr. Lafferty

Drawing SAS Triangles SAS Triangles Side Side Angle 31-Mar-17
Created by Mr. Lafferty

Drawing SAS Triangles Toolkit required Ruler 2. Protractor
3. Pencil & Paper 31-Mar-17 Created by Mr. Lafferty

Drawing SAS Triangles Example : Draw to scale the triangle ABC
with AB = 6cm and angle CAB = 30o and AC = 5cm A Step 1 Draw line AB=6cm Step 2 Measure angle CAB from A C X Step 3 Draw the line AC = 5cm through X. Label it C. A B Step 4 Join C to B. Check angles add to 180o 31-Mar-17 Created by Mr. Lafferty

Some practice Teejay Book Page 169 Exercise 1 Drawing SAS Triangles
31-Mar-17 Created by Mr. Lafferty

(ASA) Starter Questions
Q1. Convert to the 24 hour clock. (a) 7:25 pm (b) 6:50 am Q2. Write down lowest common multiple of 3, 4 , 5. Q3. List the first 4 prime numbers. Q4. Round the following to nearest 1000. (a) 12,501 (b) 369,765 31-Mar-17 Created by Mr. Lafferty

Part 2 : ASA triangles Drawing SAS Triangles 31-Mar-17
Created by Mr. Lafferty

Drawing ASA Triangles Aim of the Lesson ‘‘We are learning to construct a triangle given two angles and the length of the side in between’. 31-Mar-17 Created by Mr. Lafferty

Drawing ASA Triangles ASA Triangles Angle Angle Side 31-Mar-17
Created by Mr. Lafferty

Drawing ASA Triangles Toolkit required Ruler 2. Protractor
3. Pencil & Paper 31-Mar-17 Created by Mr. Lafferty

Drawing ASA Triangles Example : Draw to scale the triangle PQR
with PQ = 8cm and angle RPQ = 30o and RQP = 40o P Step 1 Draw line PQ Step 2 Measure Angle RPQ from P R Step 3 Measure angle RQP from Q Q P Step 4 Intersection point is R Check angles add to 180o 31-Mar-17 Created by Mr. Lafferty

Some practice Teejay Book Page 171 Exercise 2 Drawing ASA Triangles
31-Mar-17 Created by Mr. Lafferty

(SSS) Starter Questions
Q1. Convert to the 12 hour clock. (a) 17:15 (b) 05:40 Q2. Write down lowest common multiple of 3, 4 , 5. Q3. List the prime numbers between 10 and 20. Q4. Round the following to nearest 100. (a) 13,551 (b) 369,449 31-Mar-17 Created by Mr. Lafferty

Part 3 : SSS triangles Drawing SSS Triangles 31-Mar-17
Created by Mr. Lafferty

Drawing SSS Triangles Aim of the Lesson ‘‘We are learning to construct a triangle given the length of three sides’. 31-Mar-17 Created by Mr. Lafferty

Drawing SSS Triangles SSS Triangles Side Side Side 31-Mar-17
Created by Mr. Lafferty

Drawing SSS Triangles Toolkit required Ruler 2. Compass
3. Pencil & Paper 31-Mar-17 Created by Mr. Lafferty

Drawing SSS Triangles Example : Draw to scale the triangle XYZ
with XY = 3cm and XZ = 5cm and YZ = 4cm X y Step 1 Draw line XY=3cm Z Step 2 Use your compass to draw part of a circle centre X radius XZ=5cm Step 3 Use your compass to draw part of a circle centre Y radius YZ=4cm X Y Step 4 Intersection point is labelled Z Step 5 Draw in line XZ and YZ to complete triangle Check angles add to 180o 31-Mar-17 Created by Mr. Lafferty

Some practice Teejay Book Page 173 Exercise 3 Drawing SSS Triangles
31-Mar-17 Created by Mr. Lafferty

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