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Finding the Fourth Proportional to 66.43, 91.68 and 38.78

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Solution

The fourth proportional to 66.43, 91.68 and 38.78 is: 53.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.43 : 91.68 = 38.78 : x
  2. Step 2: Convert to fraction form
    66.43/91.68 = 38.78/x
  3. Step 3: Cross multiply
    66.43x = 91.68 × 38.78
  4. Step 4: Simplify right side
    66.43x = 3,555.16
  5. Step 5: Solve for x
    x = 3,555.16/66.43
  6. Step 6: Final answer
    x = 53.52

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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.