The decimal that you wrote is mixed non terminal decimal. Which means all the number don't repeat themselves.
The denominator of a non terminating decimal is always 9 even though it depends on the type of the decimal, whether it is simple or mixed
The denominator of the given decimal is 90. The denominator is 2 digit number since the given decimal is also 2 digit decimal even though it is under repeating bars.
And the numerator is 10, 13-3.
We subtract 3 since it is the one repeating itself.
To form a linear pair means that when added, they equal 180 degrees. but if they have equal measures....180/2 = 90...then they would both equal 90 degrees.....and 90 degrees is a right angle. So ABC and CBD are both right angles