Question

line AB is tangent to circle C at point B...Which of the following is not true?

Answer 1

\[\angle CAB < \angle ACB\]
\[AB^2 + BC^2 = AC^2 \]
\[\angle CAB and \angle ACB are complements\]
\[Line AB is perpendicular \to line BC\]

Answer 2

These are the options on my review

Answer 3

so B is true...

Answer 4

and A

Answer 5

I assume that the centre of the circle is C .
(a) is not necessarily true .
(b) is always true (rt angle)
(c)true (since they sum up to 90)
(d)true (since tangent at any point is perpendicular to radius through that point )

Answer 6

oh...so for A it could be a smaller angle sometimes?

Answer 7

see the above picture they cannot be compared

Answer 8

oh ok that makes sense....I get why D is true...but how do u know they are complements for C?

Answer 9

A is complement to B if A+B=90 ,
here both those angles add up to 90 , because the 3rd angle is 90 and sum of angles in a triangle is 180

Answer 10

Got it! thank you!!!