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Finding the Fourth Proportional to 66.42, 91.62 and 38.78

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Solution

The fourth proportional to 66.42, 91.62 and 38.78 is: 53.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.42 : 91.62 = 38.78 : x
  2. Step 2: Convert to fraction form
    66.42/91.62 = 38.78/x
  3. Step 3: Cross multiply
    66.42x = 91.62 × 38.78
  4. Step 4: Simplify right side
    66.42x = 3,553.02
  5. Step 5: Solve for x
    x = 3,553.02/66.42
  6. Step 6: Final answer
    x = 53.49

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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.