Complete angle

A ray of light incident on the horizontal surface of a glass slab at 70^@ just grazes the adjacent vertical surface after refraction. Complete the critical angle and refractive index of glass.

If x^(@) is the measure of an angle which is equal to its completment and y^(@) is the measure of an angle which is equal to its supplement, then find (x^(@))/(y^(@))

In the figure , angle LMN = angle LKN = 90^(@) seg MK bot seg LN . Complete the following activtiy to prove R is the midpoint of seg MK .

In the table given below, dimensions and angles of various crystals are given. Complete the table by filling the blanks.

In the table given below, dimensions and angles of various crystals are given . Complete the table by filling the blanks.

Given : square ABCD is cyclic. /_DCE is an exterior angle of square ABCD. To Prove : /_DCE = /_BAD Complete the proof by filling the boxes.

Statement-I: In a clock,minutes hand completes one rotation in one hour and hours hand completes one rotation in 12 hours. Statement II: Angles can be classified into various types based on the amount of rotation made by the terminal side with respect to initial side of an angle.

A plane is going in circles around an airport. The plane takes 3 minutes to complete one round. The angle of elevation of the plane from a point P on the ground at time t seconds is equal to that at time (t + 30) seconds. At time (t + x) seconds, the plane mes vertically above the point P. What is x equal to ?

The ratio of the times of 99.9 % of the reaction to complete and half of the reaction to complete is