In an isosceles triangles ABC, AB=AC the median drawn on the same arms are perpendicular to each other find AB/BC?

ABC is an isosceles triangle with AB = AC. The side BA is produced to D such that AB = AD. If ∠ABC = 30°, then ∠BCD is equal to 

In ΔABC, AB = AC and ∠B = 40 °, find the value of ∠A.

If ABCDEF is a regular hexagon, then what is the value (in degrees) of ∠ADB? 

What is the length of the radius of the circumcircle of the equilateral triangle, the length of whose side is 6√3 cm?

The Median of an isosceles triangle ΔABC is AD and ∠A = 110 °, AB = AC, find the value of ∠ADB.

The area of a circle is proportional to the square of its radius. A small circle of radius 3 cm is drawn within a larger circle of radius 5 cm. Find the ratio of the difference between the area of the larger circle and that of the smaller circle to the area of the larger circle.