If one angle is half of its complementary angle, find that angle.

ABCD is a trapezium in which AB is parallel to CD and AB = 4 ( CD ) . The diagonals of the trapezium intersects at O. what is the ratio of area of triangle DCO to the area of the triangle ABO ?

If the circumradius of an equilateral triangle ABC is 8 cm, then what is the height of the triangle?

X and Y are centres of circles of radius 9 cm. and 2 cm respectively XY=17 cm. Z is the centre of a circle of radius r cm which touches the above circles externally. Given that - ∠xzy = 90^o the value of r is -

ΔABC is similar to ΔDEF. Length of AB is 18 cm and  length of the corresponding side  DE is 10 cm. What is the ratio  of Perimeter of ΔABC : Perimeter of ΔDEF?

In ΔABC, ∠C=90° and CD is perpendicular to AB at D. If AD/BD=$$ {\sqrt{k}}$$, then AC/BC=?

Find the second diagonal of a rhombus when it’s first diagonal length is 12 cm and its side is 10 cm?

In any triangle ABC, AB + BC = 12 cm, BC + CA = 14 cm and CA + AB = 18 cm. What will be length of radius of a circle, if the perimeter of circle is equal to the perimeter of triangle ABC?