Substitute the value that we alreay know to find ∠3.
⇒ 77° + ∠3 = 180°
⇒ ∠3 = 180° - 77° = 103°
∠4 is equal to the measures of two nonadjacent interior angles, the sum of angles is always 180° so ∠1 +∠2 + ∠3 = 180°. In summary ∠4=sum of the measures of the two nonadjacent interior angles.
Hope this helps, have a BLESSED AND WONDERFUL DAY! As well as a great Black History Month and Valentine's day! :-)
This is theoretical probability. The 7 pieces of paper each bear one number from {1, 2, ... , 6, 7}. There is only one piece of paper marked 7. So the probability of drawing a 2 is 1/7.