90° is equal to   or 1.5707 radians.
 or 1.5707 radians.
Step-by-step explanation:
Step 1:
If an angle is represented in degrees, it will be of the form x°.  
If an angle is represented in radians, it will be of the form  radians.
 radians.
To convert degrees to radians, we multiply the degree measure by  .
.
For the conversion of degrees to radians,
the degrees in radians = (given value in degrees)( ).
).
Step 2:
To convert 
90°,

 radians.
 radians.
So 90° is equal to  or 1.5707 radians.
 or 1.5707 radians.