Explain as well since i need to know material for the test

3a)

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How I got this

a+b+e = 180

c+d+f = 180

angles 'e' and 'f' are marked in the attached drawing below (see figure 1)

Add the two equations to get

(a+b+e)+(c+d+f) = 180+180

a+b+e+c+d+f = 180+180

a+b+e+c+d+f = 360

(a+b+c+d)+(e+f) = 360

(a+b+c+d)+(140) = 360 substutition (see below)

a+b+c+d = 360-140

a+b+c+d = 220

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3b)

The angles of the triangles add to 180 degrees each. The three angles e, f, and 40 add to 180 as well as they form a straight angle, so e+f+40 = 180 leading to e+f = 180-40 = 140. This will help us with the substitution rule I marked above

So the idea is you add up all the angles, and then take away the angles we don't want (e and f) so we end up with the sum of a+b+c+d

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4

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Explanation:

Check out the attached image figure 2.

Angle DAE is given to be 30 degrees. Angle ADC is also equal to 30 because they are alternate interior angles.

Angle DCB is 40 degrees. The missing angle x of the triangle DCB is unknown for now, but we can solve for x

x+40+30 = 180

x+70 = 180

x = 180-70

x = 110

Therefore the purple angle marked in that diagram is 180-x = 180-110 = 70

The reflex angle to the 70 degree angle is 360-70 = 290

which is the shaded angle we want to determine

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.

ratio is 2 : 9

the answer is three

13.5 : 3