MSE2183
2020
ASSIGNMENT 2 FEEDBACK
UNIQUE NUMBER –
CHAPTERS 1- 4
General concerns
● Most marks were lost for incomplete work: omission of Section A questions, omission of some
lessons/parts of lessons in Section B.
● Some photocopied assignments were hard to read.
● Diagrams when drawn should be fully labelled.
SECTION A (Study guide)
1.1. Activity 3.4
Calculate the value of the letters and state the conjecture you have used to find the answer (O is the centre
of each circle).
1.1.1.
70 = 2a (angle at centre = 2x angle at circumference; angle subtended by an arc/chord at centre =
angle subtended by same arc/chord at circumference)
70
a= = 35°
2
1.1.2.
, b=2 ×30 ° (angle at centre = 2 x angle at circumference)
= 60°
3.4.3.
c = 17° (angle subtended by chord; angles on the same segment are equal)
3.4.4.
(i) d = 90° (angle subtended by a diameter)
(ii) e = 90° ( e+d = 180° ; opp. Angles of a cyclic quard
(iii) 25° + f + e = 180 ° (sum of angles of a triangle)
25° + f + 90° = 180°
f = 180° - 115° = 65 °
3.4.5.
, (i) 2g = 78° (angle at centre = twice angle at circumference)
78
g=
2
= 39°
(ii)
OB = OC (radii) ∴ ∆ OBC is an isosceles triangle
∠B = ∠h (base angles of an isosceles triangle are equal)
h+ h+ 78°=180° (Sum of angles of a triangle)
2 h=180 °−78 °
2 h=102 °
∠h=51°
6.
AB is a diameter
∠B1 + 21° = 90° (angles subtended by a diameter)
∠B1 = 90°−21 °
∠B1 = 69°
AO=OB (radii)
∴ ∠i = ∠B1 = 69° (base angles of an isosceles triangle)
7.
2020
ASSIGNMENT 2 FEEDBACK
UNIQUE NUMBER –
CHAPTERS 1- 4
General concerns
● Most marks were lost for incomplete work: omission of Section A questions, omission of some
lessons/parts of lessons in Section B.
● Some photocopied assignments were hard to read.
● Diagrams when drawn should be fully labelled.
SECTION A (Study guide)
1.1. Activity 3.4
Calculate the value of the letters and state the conjecture you have used to find the answer (O is the centre
of each circle).
1.1.1.
70 = 2a (angle at centre = 2x angle at circumference; angle subtended by an arc/chord at centre =
angle subtended by same arc/chord at circumference)
70
a= = 35°
2
1.1.2.
, b=2 ×30 ° (angle at centre = 2 x angle at circumference)
= 60°
3.4.3.
c = 17° (angle subtended by chord; angles on the same segment are equal)
3.4.4.
(i) d = 90° (angle subtended by a diameter)
(ii) e = 90° ( e+d = 180° ; opp. Angles of a cyclic quard
(iii) 25° + f + e = 180 ° (sum of angles of a triangle)
25° + f + 90° = 180°
f = 180° - 115° = 65 °
3.4.5.
, (i) 2g = 78° (angle at centre = twice angle at circumference)
78
g=
2
= 39°
(ii)
OB = OC (radii) ∴ ∆ OBC is an isosceles triangle
∠B = ∠h (base angles of an isosceles triangle are equal)
h+ h+ 78°=180° (Sum of angles of a triangle)
2 h=180 °−78 °
2 h=102 °
∠h=51°
6.
AB is a diameter
∠B1 + 21° = 90° (angles subtended by a diameter)
∠B1 = 90°−21 °
∠B1 = 69°
AO=OB (radii)
∴ ∠i = ∠B1 = 69° (base angles of an isosceles triangle)
7.
