You know the missing side of the bottom base is 6 because of the 30 60 90 special right triangle. The height is 6sqrt3 because of what i said above too, The area of a trapezoid is 1/2 b1+b2*h so 30+36*6sqrt3 is 396sqrt3 divided by 2 is 298sqrt3
Adding the 2 known angles: 60° + 100° = 160° We subtract this from 180°. 180° – 160° = 20°. Our missing angle is 20°. To find a missing angle in a triangle we subtract the two known angles from 180°.
