In a triangle, if orthocentre, circumcentre, incentre and centroid coincide, then the triangle must be

In ΔABC, D is a point on side BC such that ∠ADC = 2∠BAD. If ∠A = 80° and ∠C = 38°, then what is the measure of ∠ADB?

If the circumradius of an equilateral triangle be 10 cm, then the measure of its in-radius is

On increasing the radius of circle by 1 cm, its area is increased by 44 cm² .The original radius of the circle is -

Areas of two similar triangles are 36 cm² and 100 cm². If the length of a side of the larger triangle is 20 cm, then the length of the corresponding side of the similar triangle is:

Which of the following biomes does not have a tree?

PK is the median and M is a centroid of triangle PQR. If PK is 15 cm, then find length of PM?

The side of a trapezium pyramid with a square base is 24 cm. and its height is 5 cm. What will be the area of its oblique surface in cm²?