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Finding the Fourth Proportional to 66.61, 100.10 and 64.78

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Solution

The fourth proportional to 66.61, 100.10 and 64.78 is: 97.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.61 : 100.10 = 64.78 : x
  2. Step 2: Convert to fraction form
    66.61/100.10 = 64.78/x
  3. Step 3: Cross multiply
    66.61x = 100.10 × 64.78
  4. Step 4: Simplify right side
    66.61x = 6,484.48
  5. Step 5: Solve for x
    x = 6,484.48/66.61
  6. Step 6: Final answer
    x = 97.35

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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.