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Finding the Fourth Proportional to 72.40, 107.78 and 71.62

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Solution

The fourth proportional to 72.40, 107.78 and 71.62 is: 106.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.40 : 107.78 = 71.62 : x
  2. Step 2: Convert to fraction form
    72.40/107.78 = 71.62/x
  3. Step 3: Cross multiply
    72.40x = 107.78 × 71.62
  4. Step 4: Simplify right side
    72.40x = 7,719.20
  5. Step 5: Solve for x
    x = 7,719.20/72.40
  6. Step 6: Final answer
    x = 106.62

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.