Question
The radii of two concentric circles are 20 cm and 25 cm.
A straight line PQRS intersects the larger circle at the points P and S and intersects the smaller circle at the points Q and R. If QR = 32 cm, then the length (in cm.) of PS is:(Approx.)Solution
In the right triangle OQM. OM = √ (20²- 16²) = √144 = 12cm In the right triangle OMS. Let RS = x cm So, (25) ² = (12) ² + (x + 16) ² (x + 16) ² = 625 – 144 = 481 x + 16 = 21.9 x=21.9 - 16 =5.9 x = 5.9 So, PS = 2 × (16 + 5.9) = 43.8 cm
58   83   133   ?    308    433
60, 100, 160, 240, ?, 460
In each of the following number series, one term is missing. Find the missing term.
7, 14, 28, 56, 112, ?
12, 19, 33, ?, 117
4, 12, 36, 108, ?, 396
945, 1890, ?, 504, 144, 32
What will come in place of the question mark (?) in the following series?
11, 13, 19, ?, 51, 81
Find the missing number, in the given number series.
60, 150, ?, 450, 450, 225
31Â Â Â 40Â Â Â 51Â Â Â 64Â Â Â 79Â Â Â Â ?
- What will come in place of the question mark (?) in the following series?
13, 15, 18, 23, 30, ?