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Finding the Fourth Proportional to 115.14, 172.72 and 66.40

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Solution

The fourth proportional to 115.14, 172.72 and 66.40 is: 99.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.14 : 172.72 = 66.40 : x
  2. Step 2: Convert to fraction form
    115.14/172.72 = 66.40/x
  3. Step 3: Cross multiply
    115.14x = 172.72 × 66.40
  4. Step 4: Simplify right side
    115.14x = 11,468.61
  5. Step 5: Solve for x
    x = 11,468.61/115.14
  6. Step 6: Final answer
    x = 99.61

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.