The central angle of sector R is 31 degrees and the central angle of sector Q is 225 degrees. what is the probability that the spinner does not land on Q or R? simplify your answer and write it as a proper fraction

1 answer

To determine the probability that the spinner does not land on sectors Q or R, we first need to find the angle measures of these sectors, and then the total angle for the entire circle.

  1. Total angle in a circle: \[ 360 \text{ degrees} \]

  2. Central angle of sector R: \[ 31 \text{ degrees} \]

  3. Central angle of sector Q: \[ 225 \text{ degrees} \]

  4. Total angle of sectors Q and R: \[ 31 + 225 = 256 \text{ degrees} \]

  5. Angle not covered by sectors Q and R: \[ 360 - 256 = 104 \text{ degrees} \]

  6. Probability that the spinner does not land on Q or R: The probability \( P \) is the angle not landing on these sectors divided by the total angle in a circle: \[ P = \frac{104}{360} \]

  7. Now, simplify this fraction: Find the greatest common divisor (GCD) of 104 and 360.

    \[ 104 = 2^3 \times 13 \ 360 = 2^3 \times 3^2 \times 5 \] The GCD is \( 2^3 = 8 \).

    Now, divide both the numerator and denominator by their GCD: \[ \frac{104 \div 8}{360 \div 8} = \frac{13}{45} \]

Thus, the probability that the spinner does not land on sectors Q or R is: \[ \boxed{\frac{13}{45}} \]