Question

Why Angles 30 , 45 , 60 and 90 are equal to π/6 , π/4 , π/3 , and π/2 respectively ?​

Answer 1

because

$\pi = 180$

180°

and hence π/6=180/6=30

π/4=180/4=45

π/3=180/3=60

Answer 2

the angles given are 30 45 60 90 are in radians

there is many two types of degree measure

1. 360 is given as
2. $2\pi \: radians$
3. a radian is the division of 1 cm radius and 1cm arc

radian = 180/pi×1 =180/3.14=57.2°approx

1. so 180 is given as

$\pi \: radians$

so to convert the degree measure to radian we use the formula

radian measure = pi/180 ×degree measure

so 30° = pi/180×30= pi /6

45°=pi/180×45=pi/4

60°=pi/180×60 =pi/3

90°=pi/180×90 =pi/2