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Finding the Fourth Proportional to 71.78, 108.15 and 71.18

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Solution

The fourth proportional to 71.78, 108.15 and 71.18 is: 107.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.78 : 108.15 = 71.18 : x
  2. Step 2: Convert to fraction form
    71.78/108.15 = 71.18/x
  3. Step 3: Cross multiply
    71.78x = 108.15 × 71.18
  4. Step 4: Simplify right side
    71.78x = 7,697.22
  5. Step 5: Solve for x
    x = 7,697.22/71.78
  6. Step 6: Final answer
    x = 107.23

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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.