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Finding the Fourth Proportional to 75.47, 104.20 and 57.15

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Solution

The fourth proportional to 75.47, 104.20 and 57.15 is: 78.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.47 : 104.20 = 57.15 : x
  2. Step 2: Convert to fraction form
    75.47/104.20 = 57.15/x
  3. Step 3: Cross multiply
    75.47x = 104.20 × 57.15
  4. Step 4: Simplify right side
    75.47x = 5,954.50
  5. Step 5: Solve for x
    x = 5,954.50/75.47
  6. Step 6: Final answer
    x = 78.90

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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.