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Finding the Fourth Proportional to 78.10, 117.10 and 39.50

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Solution

The fourth proportional to 78.10, 117.10 and 39.50 is: 59.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.10 : 117.10 = 39.50 : x
  2. Step 2: Convert to fraction form
    78.10/117.10 = 39.50/x
  3. Step 3: Cross multiply
    78.10x = 117.10 × 39.50
  4. Step 4: Simplify right side
    78.10x = 4,625.45
  5. Step 5: Solve for x
    x = 4,625.45/78.10
  6. Step 6: Final answer
    x = 59.22

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.