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The value of sin A sin (60 – A) sin (60 + A) :-
C twice efficient as A, B takes thrice as many days as C. A takes 12 days to finish the work alone. If they work in pairs (i.e. AB, BC, CA) started with AB on first day and BC on second and AC on third and so on, then how many days are required to finish the work?
A does in 12 days.
C does in 6 days.
B does in 18 days.
Let total work be 36 units
If cosθ + secθ = √3 then, the value of cos3θ + sec3θ
The ratio of the areas of the circumcircle and the incircle of a square is
Let the side of the square = a
ABC is a right triangle and BD is perpendicular to AC. Find the length of AD + DC + BD.
Let AD = x
And DC = y, BD = z
Now,
62 + 82 = (x + y)2
x + y = 10 …..(i)
Also,
z2+x2 = 36 ….(ii)
and z2 + y2 = 64……..(iii)
Subtracting (ii) from (iii), we get
y2 –x2 = 28
(y-x)(y+x)=28
y-x=2.8 ……(iv)
From (i) and (iv)
y = 6.4
And so, x = 10 – 6.4 = 3.6
z2 = 82 – y2 = 82 – (6.4)2
z = 4.8
AD + DC + BD = 3.6 + 6.4 + 4.8 = 14.8
Given PQRS is a square. A circle is inscribed in the square. AB is the diameter of the circle and C is the mid-point of PQ. Given PQ = 8 m. What is the area of shaded portion?
Area of square PQRS = 8 × 8 = 64 m2
AB = PQ =8 m, radius of circle = 4 m
Area of circle = π r2 = 22//7 × 4 × 4 = 50.28 m2
Remaining area= (64 – 50.28) m2 = 13.72 m2
O is the centre of circle and ∠DAB = 50°. Calculate the value of x and y.
∎ ABCD is a cyclic quadrilateral
y + 500 = 1800
y = 1300
In, ∆ OAB
OA = OB = Radius
∠ OAB = ∠ OBA
∠ AOB = 1800 – (50 + 50) = 800
x = 180 – 80 = 1000
What is the value of cos20º + cos23º + cos26º + …. + cos2 90º ?
2 0º + cos2 3º + cos2 6º + ……. + cos2 90º
cos2 0º = 1, cos2 90º = 0
cos2 3º + cos2 6º + ……… + cos2 84º + cos2 87º = cos2 3º + cos2 6º + ……….. + sin2 6º + sin2 3º
= 1 + 1 x 14 + 1/2 = 15.5
ABCD is a cyclic quadrilateral. The side AB is extended to E in such a way that BE = BC. If ∠ ADC = 70º, ∠ BAD = 95º, then ∠ DCE is equal to –
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