A circle of radius r cm has a diameter of length r cm (b) 2r cm (c) 4r cm (d) `r/2c m`

In figure,a right triangle ABC,circumscribes a circle of radius r.If AB and BC are of length 8 cm and 6 cm respectively, find the value of r.

A circle of radius 5 cm is drawn and another circle of 3 cm radius is cut out of this circle. What is the radius of a circle which has the same area as the area of the bigger circle excluding the cut one? (a) 2 cm (b) 3 cm (c) 4 cm (d) 4.5 cm

A triangle with sides 13cm,14cm and 15cm is inscribed in a circle.The radius of the circle is (a) 2cm (b) 3cm (c) 4cm (d) 8.125cm

A sphere of radius 6 cm is melted and made three small spheres of radius 3 cm, 4 cm and r cm respectively, the value of r is ....................

In a circle of radius r, chords of length a and b cm subtend angles theta and 3 theta , respectively,at the center.Show that r=a sqrt((a)/(3a-b))cm

Assertion (A) : In a circle of radius 6 cm, the angle of a sector 60^(@) . Then area of sector is 18 (6)/(7) cm^(2) Reason (R) : Area of circle with radius r is pi r^(2)

A B C D is a trapezium in which A B D Cdot If a r( A B D)=24\ c m^2a n d\ A B=8\ c m , then height of A B C is 3 cm (b) 4 cm (c) 6 cm (d) 8 cm

If the area of a sector of a circle bounded by an arc of length 5pi cm is equal to 20pi\ c m^2 , then the radius of the circle is (a) 12 cm (b) 16 cm (c) 8 cm (d) 10 cm

The specific resistance rho of a thin wire of radius r cm, resistance R ohm and length L is given by rho = (pi r^2R)/(L). If L =78+-0.01cm r = 0.26 +- 0.02 and R =32 +- 1 Omega, What is the percentage error in rho?

A right triangle ABC,circumscribes a circle of radius r.If AB and BC are of lenths 5cm and 6cm respectively,find the value of r.