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Finding the Fourth Proportional to 66.35, 91.55 and 38.72

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Solution

The fourth proportional to 66.35, 91.55 and 38.72 is: 53.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.35 : 91.55 = 38.72 : x
  2. Step 2: Convert to fraction form
    66.35/91.55 = 38.72/x
  3. Step 3: Cross multiply
    66.35x = 91.55 × 38.72
  4. Step 4: Simplify right side
    66.35x = 3,545.04
  5. Step 5: Solve for x
    x = 3,545.04/66.35
  6. Step 6: Final answer
    x = 53.43

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.