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Finding the Fourth Proportional to 71.90, 107.79 and 42.98

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Solution

The fourth proportional to 71.90, 107.79 and 42.98 is: 64.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.90 : 107.79 = 42.98 : x
  2. Step 2: Convert to fraction form
    71.90/107.79 = 42.98/x
  3. Step 3: Cross multiply
    71.90x = 107.79 × 42.98
  4. Step 4: Simplify right side
    71.90x = 4,632.28
  5. Step 5: Solve for x
    x = 4,632.28/71.90
  6. Step 6: Final answer
    x = 64.42

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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.