Ian asked in Science & MathematicsMathematics · 1 month ago

# Find the value of x?

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• 1 month ago

Angle CBF = 81° = Vertically opposite angle ABD

Since PQ and CD are parallel to each other,

Angles  QAB and ABD are co-interior angles. Hence --

QAB + ABD  =  180°

=>  (5 x + 9)  +  81°  =  180°

=>  5 x + 90°  =  180°

=>  5 x  =  90°

=>  x  =  18  ....................................... Answer

• 4 weeks ago

x = do your own homework

• David
Lv 7
1 month ago

The value of x = 18 degrees because alternate angles are equal and there are 180 degrees on a straight line

• 1 month ago

(5x+9)+y=180 (Angle on a straight line)

but y=81 (supplementary angles are equal)   Thus (5x+9) + 81 = 180.    Remove brackets: 5x + 9 + 81 = 180. Collecting like terms, 5x=180-9-81.  Thus, 5x=180-90.   5x=90.  x=90/5.  x=18

• 1 month ago

(5x + 9) + 81 = 180

5x + 90 = 180

5x = 90

x = 18Thus, the value of x would be equal to 18 degrees.

• 1 month ago

5x+9+81=180

=>

5x=180-9-81

=>

5x=90*

=>

x=18*

• 1 month ago

(5x + 9) + 81 = 180

x = 18

• rotchm
Lv 7
1 month ago

Therefore, the obtuse angle to the right of the 81 is (180 - 81) = 99. [why?].

Now, this 99 is the same figure, same angle as the 5x+9.  [why?]

Thus, 99 = 5x+9.

Just solve for x. You know how to do that?

Done!

Hopefully no one will spoil you the answer thereby depriving you from your personal enhancement; that would be very inconsiderate of them.

• Robert
Lv 7
1 month ago

a and b are parallel lines,

so (5x + 9) + 81 = 180

You can take it from there.