2. Calculate the missing angles in each of the following. Justify your answers in as many ways as possible, using the following terms: corresponding, vertically opposite, alternate, straight angle. (i)
(ii) A B 113° D E F G H (iv) A C
103° D
E F G H (i) (i)
(i) (i)
x
115° 115°x
(i) (i)
(ii) 115° 115°
(ii) (ii)
(ii) (ii)
(v) E G
F C
A B D
118° A
C E
133° G
(vi) B
D F
85° H (iii) x (iv) (iv)
(iv) (iv)
57° 57° (i) (i) x x x
115°x x
x x
31° 115° 31°
(iv) (iv) 57°
57° 14 (i)
31° 31°
53° 53° y 10
14 y
57° 57°
x x
31°35° 31°35°
35° 35°
35° 35°
x x (v) (v)
53° 53°
(ii) 14
(v)
(4x + 1)° (4x + 1)°
53° 53°
38° 38°
(v)(4x + 1)°(4x + 1)° (4x + 1)°(4x + 1)°27° 27°
(v) (v)
38°27° 38°27°
a°(ii) 10 a° (ii)b° x (iv) p (iv) p a – 3 6 x (iv) 5 p a – 3 6 5 a – 3
5. Find the value of x in the following circles. Justify your answer in each case. (i)
(i) O O (i) (i) x°x° (i) (i) x°x° O O (ii) O O (ii) x°x° x°x° O O (ii) (ii) 35° 35° x°x° (ii) O O (ii) x°x° 35° 35° O O (iii) (iii) (iii) (iii) 35° O x° 35° O x° (iii) (iii) O x° O x° O x° O x° x (v) 6 101° (v) 2m°n° 70° 2m° 2m°n°
38° 38°
x x
(iii)
(iii) (iii)
50° 50°
x x
(vi) (vi)
27° 27°
a° b° (iii) b° (iii) 10 6
80° (3x + 2)°
80° (3x + 2)°
(iii) (iii)
50° 50°
119° 119°
(vi) (vi)
A B C D
E G
80° (3x + 2)°
80° (3x + 2)°
50° 50°
(3x+2)°(3x+2)° (3x+2)° (3x+2)°(3x+2)° (3x+2)°
119° 119°
4. Calculate the value of the unknown variables in each of the following. Justify the steps used in each case. y
(iii) 3.5 101° (v) 5 101° 70° (vi) n° 70° (vi) m s r 6 (vi)
k + 4 8k + 4 8 k + 4 8 m11
m11 11 3.5 s r 6 3.5 s r 81° H
3. Calculate the value of x in each of the following. Justify the steps used in each case. (ii)