Page 235 - Start Up Mathematics_8 (Non CCE)

Classify each of them on the basis of the following.

(a) Simple curve (b) Simple closed curve (c) Polygon
(d) Convex polygon (e) Concave polygone
2. Find x in the following figures.

(a) (b)
125°
60°

x°
70°
125°
x
3. How many sides does a regular polygon have if each of its interior angles is 165°?

4. (a) What is the minimum interior angle possible for a regular polygon? Why?
(b) What is the maximum exterior angle possible for a regular polygon?
5. Can a quadrilateral ABCD be a parallelogram if

(i) ∠D + ∠B = 180°? (ii) AB = DC = 8 cm, AD = 4 cm and BC = 4.4 cm?
(iii) ∠A = 70° and ∠C = 65°?
E P
x
y
6. The adjacent figure HOPE is a parallelogram. Find the angle measures x, y
and z. State the properties you use to find them.
40°

H z 70°
O
A D
7. ABC is a right-angled triangle and O is the mid point of the side
opposite to the right angle. Explain why O is equidistant from A, B O
and C. (The dotted lines are drawn additionally to help you).
B C

Exemplar Problems

1. Which of the following figures do not satisfy any of the following properties?

– All sides are equal.
– All angles are right angles.
– Opposite sides are parallel.

(a) (b) (c) (d)

2. Which one has all the properties of a kite and a parallelogram?
(a) Trapezium (b) Rhombus (c) Rectangle (d) Parallelogram

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