S S L C EXAMINATION , MARCH - 2021 S1635 MATHEMATICS – ANSWER KEY Qn no. For questions from 1 to 5 one score each . 1 Answer . 7 , 9 , 11 ,... 2 Answer. Square ( opposite angles are supplementary ) 3 Answer. ( 2 , 0 ) ( y - coordinate of any point on the x - axis is zero ) 4 Answer. 12 ( The sides of a triangle of angels 30 0 , 60 0 , 90 0 are in the ratio 1: √ 3:2 ) SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
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S S L C EXAMINATION , MARCH - 2021
S1635 MATHEMATICS – ANSWER KEY
Qn no.
For questions from 1 to 5 one score each .
1
Answer .
7 , 9 , 11 , . . .
2
Answer.
Square ( opposite angles are supplementary )
3
Answer.
(2 , 0) ( y - coordinate of any point on the x - axis is zero )
4
Answer.
12 ( The sides of a triangle of angels 300 , 600 , 900 are in the ratio
1 : √3 : 2 )
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
5
Answer.
Slope =7−53−2
=21
= 2
For questions from 6 to 10 carries 2 scores each .
6
Answer.
First term = 3 + 2 = 5 Common difference = 3
7
Answer.
∠ ACB = 900 ( Angle on a semicircle is right )
∠ ADB =902
= 450
8
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
Answer.
Total number of results = 9
a ) Favourable results = 1 , 3 , 5 , 7 , 9
Probability of being an odd number = Number of favourable resultsTotal number of results
=59
b ) Probability that the number will not be an even number =
Probability of being an odd number = Number of favourable resultsTotal number of results
=59
9
Answer.
OA = OB = OC = OD = 3
a ) Coordinates of O = (0 , 0)
b ) Coordinates of C = (0 , 3)
10
Answer.
x2− 1 = x2
− 12= (x + 1) (x − 1)
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
For questions from 11 to 20 carries 3 scores each .
11
Answer.
a ) Tenth term = a + 10
b ) Common difference = a+2−(a+1) = 1
c) Algebraic form = a + n ( dn + f − d = 1n + a + 1 − 1 = n + a )
12
Answer.
13
Answer.
a ) 2 , 4 , 6 , . . .
b ) x (x +2)+1 = 289 > x2+ 2x + 1 = 289 ==> (x+1)2
= 289
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
14
Answer.
a ) PA = 10 − 4 = 6 cm
b ) PA × PB = PC × PD ==> 6 × 4 = 3 × PD
PD =6 × 4
3= 8 cm
15
Answer.
a ) 2
b ) OA2+ PA2
= OP2 ==> 52+ PA2
= 132
52+ PA2
= 132
PA2= 169 − 25 = 144 ==> PA = √144 = 12 cm
16
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
Answer.
Coordinates of B = (6 , 0)
Coordinates of C = (1 , 5)
Coordinates of D = (−4 , 0)
17
Answer.
a ) sin A =Opposite side of ∠A
hypotenuse=
24k
==> k = 25
b ) cosC =Adjacent side of ∠C
hypotenuse=
2425
sinC =Opposite side of ∠C
hypotenuse=
725
18
Answer.
a ) Slant height of the cone = Radius of the sector = 12 cm .
b ) x360
=rR
==> 120360
=r
12
r =12×120
360= 4 cm
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
19
Answer.
a ) ∠ OAP = 900
b )
20
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
Answer.
DP = CP
a ) Probability that the dot would be inside the triangle APB =
Area of triangle APBArea of the rectangle
=
12×AB×h
AB×AD=
12×AB×AD
AB×AD=
12
b ) Area of triangle ADP =12
× DP×AD=12×CD
2×AD =
12×
AB2
×AD
= 14×AB×AD
c) Probability that the dot would be inside the triangle ADP =
Area of triangle ADPArea of the rectangle
=
14×AB×AD
AB×AD=
14
For questions from 21 to 30 carries 4 scores each .
21
Answer.
a ) x20 = f + 19d = 5 + 19×5 = 5 + 95 = 100
b ) S20 =202
(x1 + x20) =202
×( 5 + 100 ) =20×105
2= 1050
c) Sum = 1050 − 20×1 = 1030
SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
22
Answer.
<ECG = 1100 ( DGCE is cyclic , opposite angles of a cyclic quadrilateral
are supplementary
<EBG = 1200 ( If one vertex of a quadrilateral is inside the circle drawn
through the other vertices , then the sum of the angles at this vertex and
the opposite vertex is greater than 1800 ) <EAG = 600 ( If one vertex of a quadrilateral is outside the circle drawn
through the other vertices , then the sum of the angles at this vertex and
the opposite vertex is less than 1800 )
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SARATH A S , GHS ANCHACHAVADI , MALAPPURAM
Answer.
24
Answer.
a ) sin A =12
==> Opposite side of ∠ Ahypotenuse
=12
==> BCAC
=12
==> AC = 2 ( BC = 1 )
b ) AB2+ BC 2
= AC2 ==> AB2+ 12
= 22 ==> AB2+ 1 = 4 ==> AB2
= 4 − 1 = 3
AB = √3
c) ∠ A = 300 ( The sides of a triangle of angles 300 , 600 , 900 are in