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Finding the Fourth Proportional to 78.62, 118.34 and 71.16

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Solution

The fourth proportional to 78.62, 118.34 and 71.16 is: 107.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.62 : 118.34 = 71.16 : x
  2. Step 2: Convert to fraction form
    78.62/118.34 = 71.16/x
  3. Step 3: Cross multiply
    78.62x = 118.34 × 71.16
  4. Step 4: Simplify right side
    78.62x = 8,420.72
  5. Step 5: Solve for x
    x = 8,420.72/78.62
  6. Step 6: Final answer
    x = 107.11

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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.