17) The line that is John is closer to certain but not exactly on certain so I'd say it's "likely"
18) Using that same example as the one above, if 0 means impossible, then 1 means certain. I'd place your label for Sara at 1.
19) Let s = sides of the square. There are 4 sides and all sides are equal so we can set up the equation 4s = 64. Divide both sides by 4. s = 16. Now add 2 to this. 16 + 2 = 18. The length of each side of the original square was 18.
20) If the scale is 1 cm : 1 meter and the height of the model is 16 cm, then the actual plane must be 16 meters.
21) 2x and 100 are supplementary angles meaning together they must add up to 180.
2x + 100 = 180 2x = 180 - 100 2x = 80 Divide both sides by 2 x = 40
22) Assuming 3x is supposed to be the right angle, right angles are 90 degrees.
