Answer :

Answers are:
64. = 18
65. = 30
66. = 38 m
67. = 32.7 km

Step by step

64. Find the missing angle. Triangles will equal 180 degrees total so subtract the two known angles from 180 to get your missing angle.
180 - 123 - 39 = 18

65. Find the missing angle. Triangles will equal 180 degrees total so subtract the two known angles from 180 to get your missing angle.
180 - 75 - 75 = 30

66. Find the perimeter. Perimeter is found by adding up all the sides of the figures.
14 + 16 + 8 = 38 m

67. Find the perimeter. Perimeter is found by adding up all the sides of the figures.
13.6 + 6 + 6.4 + 6.7 = 32.7 km