1.The diagonals AC and BD of a ∥ gm ABCD intersect each other at the point O such that ∠DAC = 50° and ∠AOB = 80°. Then ∠DBC =?
(a) 50°
(b) 40°
(c) 45°
(d) 30°
2.The perimeter of ∥ gm is 22 cm. If the longer side measures 6.5 cm. what is the measure of the shorter side?
(a) 5.5 cm
(b) 4.5 cm
(c) 6.0 cm
(d) 5.0 cm
3.If an angle of a ∥ gm is tow- third of its adjacent angle, then the largest angle of ∥ gm :
(a) 72°
(b) 60°
(c) 108°
(d) 120°
4.PQRS is a square. The ∠SRP is equal to :
(a) 90°
(b) 45°
(c) 100°
(d) 60°
5.ABCD is a rhombus with ∠ABC = 50°, then ∠ACD is:
(a) 50°
(b) 90°
(c) 65°
(d) 70°
6.PQRS is a ∥ gm. PX and QY are respectively, the perpendicular from P and Q to SR and SR produced. Then PX is equal to :
(a) QY
(b) 2QY
(c) ½ QY
(d) XR
7. ABCD is a ∥gm CL ⊥ AD and DM ⊥ BA. If CD = 16 units, DM = 12 units and CL = 15 units, then AD = ?
(a) 12. 8 units
(b) 13.6 units
(c) 11.1 units
(d) 12.4 units
8.In a parallelogram ABCD, AO and BO are the bisectors of ∠A and ∠B respectively, then ∠AOB is equal to :
(a) 60°
(b) 120°
(c) 100°
(d) 90°
9.If one of the interior angles of a regular polygon is equal to 5/6 times of one of the interior angles of a regular pentagon, then the no. of sides of the polygon:
(a) 3
(b) 4
(c) 6
(d) 8
10.Difference between the interior and exterior angles of regular polygon is 60°. The number of sides in the polygon is:
(a) 5
(b) 6
(c) 8
(d) 9
ANSWERS AND SOLUTION
1.(d) ∠ACB = ∠DAC = 50° (Alternate interior ∠s)
∠BOC = 180° – 80° = 100°
so Now, in ∆BOC
∠OBC = 180° – (100° + 50°) = 30°
2.(b) Perimeter of ∥ gm = 22cm
=> 2(a + b) = 22cm => a + b = 11
=> b = 11 – a => 11 - 6.5 = 4.5cm
so shorter side, b = 4.5cm
3.(c) Since, adjacent angles of a ∥ gm are supplementary.
so x + 2/3 + x = 180°
=> 5x/3 = 180°
=> X = 108°
so 2/3x + 2/3 * 108° = 72°
so Agnles are = 108°, 72°, 108°, 72°
so largest angle = 108°
4.(b) PQRS is square, SP = SR and ∠S = 90°
and ∠SRP= ∠SPR=1/2(90°)=45°
Hence, ∠SRP = 45°
5.(c) Since, AB = BC
so ∠BAC=∠BCA= 1/2 (180°-50°)
= 65°(AB = BC)
so ∠ACD = ∠BAC=65°
[AB ∥ DC]
6.(a) In ∆PSX and ∆QRY
∠x= ∠y=90° and SX=RY
(sx= SY – XY and RY = SY-SR= SY – PQ = SY – XY]
And PS = QR (sides of a ∥ gm)
SO ∆PSX ≅ ∆QRY (R.H axion)
SOPX = QY
7.(a) Area of ∥ gm ABCD = Base * height
=>AB * DM = AD * CL
=> 16 * 12 = AD * 15
=> AD = 12.8 units
8.(d)
9.(b) interior agnle of pentagon = 180° – 360°/5 = 108°
so Interior angle of required polygon = 5/6 * 108°= 90°
so Each exterior angle of the required polygon = 180°-90°=90°
so No.of sides = 360/90 = 4
10.(b)
∠BOC = 180° – 80° = 100°
so Now, in ∆BOC
∠OBC = 180° – (100° + 50°) = 30°
2.(b) Perimeter of ∥ gm = 22cm
=> 2(a + b) = 22cm => a + b = 11
=> b = 11 – a => 11 - 6.5 = 4.5cm
so shorter side, b = 4.5cm
3.(c) Since, adjacent angles of a ∥ gm are supplementary.
so x + 2/3 + x = 180°
=> 5x/3 = 180°
=> X = 108°
so 2/3x + 2/3 * 108° = 72°
so Agnles are = 108°, 72°, 108°, 72°
so largest angle = 108°
4.(b) PQRS is square, SP = SR and ∠S = 90°
and ∠SRP= ∠SPR=1/2(90°)=45°
Hence, ∠SRP = 45°
5.(c) Since, AB = BC
so ∠BAC=∠BCA= 1/2 (180°-50°)
= 65°(AB = BC)
so ∠ACD = ∠BAC=65°
[AB ∥ DC]
6.(a) In ∆PSX and ∆QRY
∠x= ∠y=90° and SX=RY
(sx= SY – XY and RY = SY-SR= SY – PQ = SY – XY]
And PS = QR (sides of a ∥ gm)
SO ∆PSX ≅ ∆QRY (R.H axion)
SOPX = QY
7.(a) Area of ∥ gm ABCD = Base * height
=>AB * DM = AD * CL
=> 16 * 12 = AD * 15
=> AD = 12.8 units
8.(d)
9.(b) interior agnle of pentagon = 180° – 360°/5 = 108°
so Interior angle of required polygon = 5/6 * 108°= 90°
so Each exterior angle of the required polygon = 180°-90°=90°
so No.of sides = 360/90 = 4
10.(b)
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