Question 155395
It seems that RST is a straight angle.

and VS ray is forming two angles   RSV and VST

if VST is acute then  RSV = 180 - VST 
as VST is acute -- less than 90

RSV = 180 - (90 - x)
RSV = 180 - 90 + x
RSV = 90 + x    > 90

Which shows that RSV is > 90  so it is always Obtuse.

I hope this is clear to you.
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