A 60 degree set square longest side is so kept that the longest side in horizontal plan makes angle 30 degrees with vertical plain and set-square itself inclined at 45 degrees to horizontal plane.
Draw projectoins of the set square.
(From JNTUK R13 1-1)

Dear Student,

Considering ABCD is a Vertical wall of your room (AB touching the floor) andABEF is the floor of it. Let PQR is a set quare with angles P = 90, Q = 60 and R = 30, So QR will be the longest side. Now according to the given situation,
Side QR is on the floor and P in the air.
Angle between AB and QR is 30 degree (with vertical wall/plane)
Angle with which set square is inclined with ABEF is 45 degree.

I Hope this explanation will help you in understanding the question more clearly.

Thanks.