Angles Revising Basic Angles Naming Angles Calculating Missing angles Angles in a Triangle Corresponding Angles Alternate Angles 17-Feb-19

Type of Angles Vertical Horizontal Obtuse Between 90o – 180o Acute less than 90o Right - Angle exactly 90o Straight Line Angle exactly 180o reflex over 180o less than 360o 17-Feb-19

QUESTION TIME! The angle highlighted is: A Acute B Right Angled C Obtuse D Straight E Reflex 17-Feb-19

Naming Angles A X B Y C Z Type of angle is acute Type of angle is obtuse Name of angle is ∠ ABC Name of angle is ∠ ZYX Or ∠ CBA Or ∠ XYZ MIDDLE LETTER IS ALWAYS THE VERTEX ALWAYS 3 CAPITAL LETTERS 17-Feb-19

Examples Name & state the type of angle for the shape below:- ∠ PQS is right angled P Q R S ∠ PRS is right angled ∠ PSR is acute ∠ RPS is acute ∠ PSQ is acute ∠ QPS is acute 17-Feb-19

QUESTION TIME! Q Which Statement is FALSE? A ∠ PQR is Obtuse B ∠ QRS is Obtuse C ∠ STR is Right Angled D ∠ RST is Acute E ∠ SRT is Acute P R S T 17-Feb-19

Calculate Missing Angles 1. 65o 2. 65o 115o 25o 120o 95o 4. 3. 34o 123o 23o 145o 17-Feb-19

QUESTION TIME! ? Calculate the missing angle. A 256° B 166° C 104° D 76° E 14° 76° ? 17-Feb-19

QUESTION TIME! ? The missing angle is 110° TRUE or FALSE? 146° 104° 17-Feb-19

Related Angles 55o 115o 35o 65o Two angles making a straight line add to 180o (Supplementary angles) Two angles making a right angle add to 90o (Complementary angles) 17-Feb-19

QUESTION TIME! Calculate the supplement of 163 °. A 13° B 17° C 73° D 197° E 343° 17-Feb-19

QUESTION TIME! Calculate the complement of 30 °. A 150° B 120° C 90° D 60° E 30° 17-Feb-19

Opposite Angles are equal. bº Opposite Angles are equal. a=b c=d c° d° 17-Feb-19

Calculate Missing Angles 1. 35o 2. 98o 145o 35o 145o 82o 82o 98o 3. 79o 43o 43o 58o 58o 79o 17-Feb-19

QUESTION TIME! n m Calculate angles m & n A m=67° & n= 67° B m=113° & n= 67° C m=67° & n= 113° D m=67° & n= 127° E m=127° & n= 67° n m 67° 17-Feb-19

angle sum of any Triangle To determine the angle sum of any Triangle Cut off corners  Cut off corners  Cut off corners  17-Feb-19

All angles in a triangle add up to 180o 180o 17-Feb-19

Calculating Missing Angles Copy out the following triangles and find the missing angles. 61° 50o xo 38o 87o xo xo xo 32o 52° 65° 65° Remember all the angles add up to 180o 17-Feb-19

Calculate the missing angle QUESTION TIME! Calculate the missing angle A 67° B 76 ° C 77 ° D 113 ° E 114 ° F 247 ° 76° ? 37° 17-Feb-19

Corresponding Angles look for Parallel Lines shapes 17-Feb-19

Corresponding Angles Which angles are equal? 17-Feb-19

Which angles are equal to the shaded angle? 17-Feb-19

QUESTION TIME! True or False? The value of x is 131°. x° 131° 17-Feb-19

What are the values of the missing angles? Example 123 57 57 What are the values of the missing angles? 123 17-Feb-19

QUESTION TIME! ? The angle marked is:- A 180° B 136 ° C 126° D 124 ° F 34 ° ? 54° 17-Feb-19

Alternate Angles Look for - Z shapes = equal angles 17-Feb-19

Example Find the value of a. 35° 35° a 17-Feb-19

Find the value of d. 123° A 180° B 123° C 190° D 57° d 17-Feb-19

Example 50 ° Find the value a and b a 130 ° b 50 ° 17-Feb-19

Example 135° Find the value of a and b. c 45° 45° d 17-Feb-19

Find the value of q A 37° B 53° C 143° D 153° E 180 ° F 223 ° q 37° 17-Feb-19

Extension Find all the missing angles 124° 56° 56° 124° 124 ° 56 ° 56° 17-Feb-19