As sum of 3 angles in triangle is 180 and angle at any straight side is 180 degrees.

If x is les than 90 the other angle in the triangle on other side is greater than 90 and hence the y can have values only les than 70

20+ 90 = 110
But based on value of x, the value of other 2 angles can only be greater than 110 hence B

If angle x is less than 90 degrees, we can express this as follows...

NOTE: (90-)° does NOT mean "negative 90 degrees"; that notation means "an angle that's less than 90 degrees"


Since angles on a line must add to 180°, we can conclude that the other angle must be more than 90 degrees, which we'll express as follows:


At this point, we know that the 3 angles in the triangle must add to 180°
So, we can write: y + 20 + (90+) = 180
Notice that 20 + (90+) = 110+ (an angle that greater than 110 degrees)
So, we can write: y + (110+) = 180

If the equation were y + 110 = 180, then we'd conclude that y EQUALS 70
However, since the equation is y + (110+) = 180, we can conclude that y is LESS THAN 70

Answer: B

Cheers,
Brent
_________________

20+y < 90

y < 70

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