A 1.6 m tall observer is 45 meters away from a tower. The angle of elevation from his eye to the top of the tower is 30°, then the height of the tower in meters is

If x=aCosθCosΦ, y = aCosθSinΦ and z= aSinθ, then the value of x2+ y2 + z2 is

The value of sec217°-1tan273°-sin17°sec73°

In an isosceles triangle ABC, AB = AC, XY || BC. If ∡A = 30, then ∡BXY =

ΔABC is an equilateral triangle and D, E are midpoints of AB and BC respectively. Then the area of ΔABC : the area of the trapezium ADEC is

ΔABC a right angled triangle has ∠B = 90° and AC is hypotenuse. D is its circumcentre and AB = 3 cms, BC = 4 cms. The value of BD is

The point where the 3 medians of a triangle meet is called

If xa+b+1=xa-b+a-ba+b, then x is equal to