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Finding the Fourth Proportional to 78.18, 117.68 and 71.26

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Solution

The fourth proportional to 78.18, 117.68 and 71.26 is: 107.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.18 : 117.68 = 71.26 : x
  2. Step 2: Convert to fraction form
    78.18/117.68 = 71.26/x
  3. Step 3: Cross multiply
    78.18x = 117.68 × 71.26
  4. Step 4: Simplify right side
    78.18x = 8,385.47
  5. Step 5: Solve for x
    x = 8,385.47/78.18
  6. Step 6: Final answer
    x = 107.26

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.