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Finding the Fourth Proportional to 75.78, 104.46 and 61.20

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Solution

The fourth proportional to 75.78, 104.46 and 61.20 is: 84.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    75.78 : 104.46 = 61.20 : x
  2. Step 2: Convert to fraction form
    75.78/104.46 = 61.20/x
  3. Step 3: Cross multiply
    75.78x = 104.46 × 61.20
  4. Step 4: Simplify right side
    75.78x = 6,392.95
  5. Step 5: Solve for x
    x = 6,392.95/75.78
  6. Step 6: Final answer
    x = 84.36

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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.