4√3cm
8cm
8√3cm
4cm
Correct answer is C
Hint: Make a sketch of an isosceles triangle with two of its sides and angles angles.
: PQ (r) = PR (q) = 8cm
: R° = Q° = 30°
Sum of angles in a triangle = 180°
P° + Q° + R° = 180°
P° + 30° + 30° = 180°
P° = 180° - 60°
p° = 120°.
: PQ = r, PR = q, QR = p
Using sine rule:
\(\frac{p}{sinP}\) = \(\frac{q}{sinq}\)
\(\frac{p}{sin120°}\) = \(\frac{8}{sin30°}\)
cross multiply
p = \(\frac{8 X sin120°}{sin30°}\)
p = \(\frac{8 X √3/2 }{1/2}\)
p = 8√3
8cm
6cm
9cm
7cm
Correct answer is B
(r/L) = (θ/360°)
Given θ = 300, and L = 7.2cm,
=> r = (300 x 7.2)/360
r = 6cm
Factorize 4x2 - 9y2 + 20x + 25
(2x -3y + 5)(2x - 3y - 5)
(2x - 3y)(2x + 3y)
(2x - 3y +5)(2x + 3y + 5)
(2x + 5)(2x - 9y +5)
Correct answer is C
Given: 4x2 - 9y2 + 20x + 25
Collect like terms: 4x2 + 20x + 25 - 9y2
(2x + 5)(2x + 5) - 9y2
(2x + 5)2 - (3y)2
(2x - 3y +5)(2x + 3y + 5)
The sixth term of an A.P is half of its twelfth term. The first term of the A.P is equal to
zero
half of the common difference
double the common difference
the common difference
Correct answer is D
1st statement: U6 = 1/2(U12)
a + (n -1)d = 1/2[a + (n-1)d]
a + 5d = a + 11d
2(a + 5d) = a + 11d
2a + 10d = a + 11d
Solving, => a = d
Hence the first term is equal to the common difference
4
zero
-2
-4
Correct answer is D
By definition a*b = a + b + 1.
Let the inverse of the element 2 be x,
Therefore 2*x = -1
i.e. 2 + x + 1 = -1
3 + x = -1
x = -1 - 3
x = -4