By reducing the circumference of a circle by 50 percent, by what percentage will its area decrease?

In a circle of radius 17 cm, two parallel chords of lengths 30 cm. and 16 cm are drawn. If both the chords are on the same side of the center, then the distance between the chords is -

Area of the triangle formed by the graph of the straight lines x - y = 0, x + y = 2 and the x-axis is: 

If  $$\sqrt{a}+\sqrt{b}=15 \ and \ (\sqrt{a}-\sqrt{b} )=3$$ then the value of $$\sqrt{ab/4} $$ is 

Find the exact value of the following question:

$$ 3{1\over2} × 3 {1\over 7}+ 5{3\over4}÷{46\over3}=?$$

Allowing 20 % and 15 % successive discounts, the selling price of an article becomes ₹ 3,060; then the marked price will be: 

Cost of a diamond varies directly as the square of its weight. A diamond broke into four pieces with their weights in the ratio 1 : 2 : 3: 4. If the loss in the total value of the diamond was Rs.7000, the price of the original diamond was

In the figure given below, AD bisects ∠BAC. If the area of ΔABD=40 cm² and AC=3AB, then the area of ΔABC: