Answer:
see explanation
Step-by-step explanation:
Using the ratio equality for circles
= 
(a)
Note the angle at the centre of the shaded arc is 360° - 90° = 270°, thus
=
=
( cross- multiply )
3C = 180 ( divide both sides by 3 )
C = 60 mm
(b)
Note the angle at the centre of the shaded arc is 360° - 135° = 225°, thus
=
( cross- multiply )
225C = 1188 ( divide both sides by 225 )
C = 5.28 cm
Selection B is appropriate.
_____
It takes 12 times as long to fill the whole tank as it does to fill 1/12 of the tank.
.. 12 * (1/3 hour) = (1/3)*12 hour
The equation to find Amy's earning after tutoring for 15 hours is 300 dollars.
<h3>How to find an equation?</h3>
She earn 20 dollars for each hours she tutors.
E = earnings in dollars
H = hours of tutoring
The equation relating E and H are as follows:
E = 20H
Therefore, the equation to find Amy's earning after tutoring for 15 hours is as follows;
E = 20H
E = 20 × 15
E = 300 dollars
Therefore, Amy's tutoring for 15 hours is 300 dollars.
learn more on expression here: brainly.com/question/14492671
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