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The hour hand of a clock is 6 inches long and the minute hand is 8 inches long. What is the ratio of the distance in inches traveled by the tip of the hour hand to the distance in inches traveled by the tip of the minute hand from noon to 3 p.m. ?

User Uxp
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2 Answers

6 votes

Final answer:

The ratio of the distances traveled by the tips of the hour hand to the minute hand from noon to 3 p.m. is 3/16. This was determined by calculating the arc lengths for each hand during this time period using the formulas for arc length and circumference of a circle.

Step-by-step explanation:

To find the ratio of the distances traveled by the tips of the hour hand and the minute hand from noon to 3 p.m., we first need to calculate the lengths of the arcs that each hand has swept during this time. Since the clock makes a full rotation every 12 hours and the hour hand has moved a quarter of this distance by 3 p.m., it has traveled through an angle of 90 degrees (1/4 of 360 degrees).

The distance traveled by the tip of the hour hand can be calculated using the formula for the arc length of a circle, which is arc length = radius × angle in radians. First, we convert 90 degrees to radians by the formula radians = degrees × (\pi / 180), which gives us \pi / 2 radians for 90 degrees. Then we multiply the length of the hour hand (6 inches) by the angle in radians to get the arc length: 6 inches × (\pi / 2) inches.

The minute hand rotates through 360 degrees every 60 minutes, so from noon to 3 p.m., it completes a full rotation. Therefore, the arc length for the minute hand is simply the circumference of the circle it describes, which can be calculated with the formula circumference = 2 × \pi × radius. The circumference for the minute hand is 2 × \pi × 8 inches.

Now, let's calculate the arc lengths: For the hour hand, we get 6 × (\pi / 2) = 3\pi inches, and for the minute hand, we get 2 × \pi × 8 = 16\pi inches. The ratio of the distances is the arc length of the hour hand divided by the arc length of the minute hand: 3\pi / 16\pi, which simplifies to 3/16. So, the ratio of the distances traveled by the tips of the hour hand to the minute hand from noon to 3 p.m. is 3/16.

User Volkan
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1 vote

Answer:

the ratio of the distance in inches travelled by the tip of the hour hand to the distance in inches travelled by the tip of the minute hand is 0.125.

Step-by-step explanation:

The given information is:

  • length of the hour hand, l = 6 inches
  • length of the minute hand, b = 8 inches

Therefore, since the tip of the minute moves from 12 to 3, it moved a distance of:

s₁ = r θ

s₁ = (8)(π/2)

s₁ = 4π inches

The hour hand moves 30 degrees / 60 = 1/2 degree in a minute.

Therefore, in 30 minutes the hour hand moves a distance of:

s₂ = r θ

s₂ = 6(30×1/2×π/180)

s₂ = π/2 inches

Therefore, the ratio of the distance in inches travelled by the tip of the hour hand to the distance in inches travelled by the tip of the minute hand is:

s₂ / s₁ = (π/2) / 4π

s₂ / s₁ = 0.125

User Marko Previsic
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