Page 388 - Start Up Mathematics_8 (Non CCE)

Answer is One Word or a Line 2. cm 3. 5 cm each
1. The fixed time interval at the end of which the interest 4. KI = 12 cm, KE = 5 cm and ET = 12 cm
is calculated and then added to the principal before the 5. x = 130° 6. 20 cm and 25 cm
beginning of the next time interval is called the conver- 7. (a) Parallelogram (b) Rhombus, Square
sion period. (c) Square, Rectangle
2. The relative increase in value is called appreciation. 8. x = 3, QS = 20 units
3. The depreciation per unit of time is called the rate of 9. (a) Rhombus, Square (b) Rectangle, Square
depreciation.
Ê ˆ Exercise 14.5
n Á R l ˜ l 1. ∠R = ∠A = 130° 2. 9 cm and 18 cm
Ê
R ˆ
4. A = P 1+ 100¯ ˜ 1 Á + m ˜ where n m = time 5. –R
Á
Ë
Ë Á 100˜ ¯ 4. x = 9, y = 5
Let’s Evaluate 5. (a) x = 50°, y = 90° (b) x = 70°, y = 130°
1. ` 2,388.30 2. ` 218 3. ` 310 4. 12.5% p.a. Review Exercises
5. Kusum, ` 4,320 6. ` 5,000 7. 1 year Multiple Choice Questions
8. 1½ years 1. b 2. a 3. c 4. d
Thinking Skills 5. a 6. b
1. ` 1,000, 10% p.a. 2. ` 8,000, 10% p.a. 3. ` 5,000 Solve Mentally
Values and Life Skills Fill in the Blanks 2. perpendicular 3. triangle
1. heptagon
1. ` 3,149.28 2. 2 years 3. 93,312 4. 5,865 4. rhombus 5. eight
Exemplar Problems Answer in One word or a Line
1 1. If a number of points on a plane surface are joined with-
1. b 2. 10%; 1 years
2 out breaking or retracing, the curve so formed is called
3. True 4. ` 10,75,840; ` 51,840 a plane curve.
5. (i) ` 5,000 (ii) ` 1,05,000 (iii) ` 5,250 (iv) ` 1,10,250 Plane curves are of three types—(a) open curve,
(b) closed curve and (c) simple closed curve.
Chapter 14 2. Convex quadrilateral: The line segment connecting any
Exercise 14.1 two points lie completely within the quadrilateral. Also,
the measure of each angle is less than 180°.
1. a, b, d, f, g 2. a, b, c 3. (a) 1,620° (b) 2,520° Concave quadrilateral: The line segment connecting any
4. 40°, 60°, 80° 5. 70° each two points does not lie completely within the quadrilateral.
7. ∠J = 80°, ∠A = 60°, ∠M = 40° Also, the measure of at least one angle is more than 180°.
Exercise 14.2 3. Properties of a kite
1. 72.5° each 2. 60°, 80°, 100°, 120° (a) None of the sides are parallel.
3. (a) 120° (b) 80° (c) 75° 4. 60° (b) The diagonals intersect at right angles (PR ⊥ SQ).
5. 64°, 80°, 96°, 120° 6. 80° each (c) The longer diagonal bisects the shorter one.
7. x = 105° and y = 120° 4. A quadrilateral in which one pair of opposite sides are
Exercise 14.3 parallel is a trapezium. An isosceles trapezium has its
1. 40°, 140°, 40°, 140° 2. 108°, 72°, 108°, 72° non-parallel sides equal while a right trapezium has two
3. 18 cm 4. 110°, 70°, 110° right angles.
5. ∠S = 45°, ∠P = 135°, ∠U = 45° and ∠N = 135° 5. (a) Opposite sides are of the same length.
6. (a) Diagonals of parallelogram bisect each other. (b) Diagonals bisect each other.
(b) Alternate interior angles are equal. Let’s Evaluate
(c) Vertically opposite angles are equal.
7. 13 cm each 8. 60°, 120°, 60°, 120° 1. 58° 2. 5 cm 3. 68°
9. (a) x = 70°, y = 110° (b) x = 10, y = 3 4. 37°, 143°, 37°, 143° 5. 90°
(c) x = 75°, y = 105° 6. ∠SNO = 95°, ∠OPA = 95°, ∠SAN = 50°, ∠ANP = 10°
Exercise 14.4 7. ∠UMP = 130° 8. ∠APB = 80°
1. (a) In a rectangle diagonals are equal. 10. x = 50°, y = 50°, z = 50° 11. ∠F = 55°
(b) ∆ COE ≅ ∆ AOP hence by CPCT. Thinking Skills
(c) Diagonals are equal and bisect each other. 1. 8 2. 12 3. 5 and 10
(d) Vertically opposite angles are equal. 4. 20 m

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