Answer:
81°
Step-by-step explanation:
By the outside angle theroem, we know that 2 * angle APC is differece of arcs DC and AB.
Angle APC = 27° so the difference is 54°
Arc DC = 27°, so Arc AB = 27° + 54° or 81°.
The answer to the above question can be explained as under -
We know that, the sum of angles of triangle is 180°.
So, vertex angle plus base angles are equal are equal to 180°.
Let the vertex angle be represented by "v" and base angles be represented by "b".
Thus, v + b + b = 180°
So, v + 2b = 180°
Next, the question says, the vertex angle is 20° less than the sum of base angles.
Thus, 2b - 20° = v
<u>Thus, we can conclude that the correct option is A) v + 2b = 180°, 2b - 20° = v</u>
<span>If you pull the edges of the right angle down it makes a straight line.
Therefore, the angles in a triangle add up to 180°
So, 35 + 45 = 80
Then, 180 - 80 = 100
The third angle = 100° </span>
