Math Problem Statement

The diagram shows the track for a bicycle race. The track consists of two parallel line segments with a semicircle at each end. The track is 10 m wide. (a) Ismail bikes on the inner edge of the track. How far does he bike in one lap, to the nearest tenth of a metre? (b) Carey bikes on the outer edge. How far does he bike in one lap, to the nearest tenth of a metre? (c) Find the difference between the distances biked by Ismail and Carey.

Solution

To solve the problem in the image, let's analyze the track and its components step by step:

Geometry of the Track

  • The track consists of two straight parallel line segments and two semicircles at the ends.
  • Inner dimensions:
    • Length of each straight segment = 110 m
    • Radius of each semicircle = 90m2=45m\frac{90 \, \text{m}}{2} = 45 \, \text{m}
  • Outer dimensions:
    • The width of the track is 10 m.
    • Radius of the outer semicircle = 45+10=55m45 + 10 = 55 \, \text{m}

Part (a): Distance Biked by Ismail (Inner Edge)

  1. Length of the two straight segments: 2×110=220m2 \times 110 = 220 \, \text{m}
  2. Perimeter of the two semicircles (inner edge): Perimeter of circle=2πr    Half circle=πr\text{Perimeter of circle} = 2\pi r \implies \text{Half circle} = \pi r So, for two semicircles: 2×(π×45)=90πm2 \times (\pi \times 45) = 90\pi \, \text{m}. Approximate π3.1416\pi \approx 3.1416: 90π282.74m90\pi \approx 282.74 \, \text{m}
  3. Total distance for one lap (inner edge): Distance=220+282.74=502.74m\text{Distance} = 220 + 282.74 = 502.74 \, \text{m} Rounded to the nearest tenth: 502.7 m

Part (b): Distance Biked by Carey (Outer Edge)

  1. Length of the two straight segments: 2×110=220m2 \times 110 = 220 \, \text{m} (same as inner edge).
  2. Perimeter of the two semicircles (outer edge): 2×(π×55)=110πm2 \times (\pi \times 55) = 110\pi \, \text{m} Approximate π\pi: 110π345.58m110\pi \approx 345.58 \, \text{m}
  3. Total distance for one lap (outer edge): Distance=220+345.58=565.58m\text{Distance} = 220 + 345.58 = 565.58 \, \text{m} Rounded to the nearest tenth: 565.6 m

Part (c): Difference in Distances

The difference between Carey’s and Ismail’s distances: 565.6502.7=62.9m565.6 - 502.7 = 62.9 \, \text{m} So, the difference is 62.9 m.

Final Answers

(a) Ismail bikes 502.7 m in one lap.
(b) Carey bikes 565.6 m in one lap.
(c) The difference is 62.9 m.

Would you like a breakdown of specific calculations or further clarifications?


Here are five related questions:

  1. How would the total lap distance change if the width of the track were increased?
  2. How does the semicircle radius affect the total lap length?
  3. What if the track were an ellipse instead of a semicircle? How would you calculate the perimeter?
  4. Can you calculate the area of the track's surface?
  5. What is the percentage increase in distance for Carey compared to Ismail?

Tip: Always verify semicircular and straight sections separately when analyzing track geometries!

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Math Problem Analysis

Mathematical Concepts

Geometry
Perimeter of Circles
Measurement

Formulas

Perimeter of a circle = 2πr
Length of semicircle = πr
Total distance = straight segments + curved segments

Theorems

Circle properties

Suitable Grade Level

Grades 8-10