_The angle between skew back of a flat arch and the horizontal, is kept approximately equal to$?

_The angle between skew back of a flat arch and the horizontal, is kep

1.	_The angle between skew back of a flat arch and the horizontal, is kept approximately equal to$?
A.	0¬¨‚àû
B.	30¬¨‚àû
C.	60¬¨‚àû
D.	90¬¨‚àû
Answer» D. 90¬¨‚àû