First of all...YOU'RE NOT DUMB!!! You just need some help! Being confident in your knowledge/skills is half the work! ;D
And second...
PART 1:
28. Polygon ABCDE is a pentagon (it has five sides). The sum of the interior angle measures for a pentagon is 540°. Here's what we know:
m<A = 90°
m<B = 90°
m<D = 90°
m<C = m<E
First, find the sum of the measures of angles A, B, and D.
(90)(3) = 270°.
Next, find the combined angle measure of angles C and E.
540 - 270 = 270°.
Finally, find the measure of angle E (or m<AED).
270 / 2 = 135°.
So, to fill in the blanks:
90 · 3 + x · 2 = 540
m<AED = 135°.
29.
(a) 360°
(b) hexagon
(c) 1080
(d) hendecagon (11 sides)
I have attached a table containing a list of polygons, their side-count, and the sum of their interior angles.
PART 2:
Complimentary angles are angles whose measures add to equal 90°.
Supplementary angles are angles whose measures add to equal 180°.
30. 35° + 55° = 90°; Complimentary.
31. 62° + 108° = 170°; Neither.
Hope this helps!