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Finding the Fourth Proportional to 78.60, 108.42 and 55.25

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Solution

The fourth proportional to 78.60, 108.42 and 55.25 is: 76.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.60 : 108.42 = 55.25 : x
  2. Step 2: Convert to fraction form
    78.60/108.42 = 55.25/x
  3. Step 3: Cross multiply
    78.60x = 108.42 × 55.25
  4. Step 4: Simplify right side
    78.60x = 5,989.66
  5. Step 5: Solve for x
    x = 5,989.66/78.60
  6. Step 6: Final answer
    x = 76.20

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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.