Question
A man on the top of a tower, standing on the sea-shore,
finds that a boat coming towards him takes 10 minutes for the angle of depression to change from 30° to 60°. How soon the boat reach the sea-shore?Solution
height of tower = h 
tan 30° = h / (x+y) tan 60° = h/x h/ √3 = x 1/√3 = h / (x+y) h√3 = x + y h√3 = h/√3 + y 2h/ √3 = y y = 2x time taken to travel y distance = 10mins time taken to travel x distance ( half of y distance) = 5 mins
If the angles of the triangle are in the ratio of 1:2:3, then what is the smallest angle?
Find the ratio between the area of the in-circle and the circum-circle of a square?
Let A, B, and C be the mid-points of sides PQ, and QR PR, respectively, of ΔPQR. If the area of ΔPQR is 64cm², then find the area of ΔABC.
...What will be inradius of an equilateral triangle of side 2 cm?
PQRS is a cyclic quadrilateral of which PQ is the diameter. Diagonals PR and QS intersect at A. If SQR = 25°, then angle PAS measures
A set of data is presented in the form of a frequency distribution table with class intervals and their respective frequencies. The lower boundary of th...
If O is circumcentre of acute angled triangle ABC, if ∠ BOC = 150˚ then ∠ BAC = ?
