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Finding the Fourth Proportional to 74.38, 111.72 and 71.43

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Solution

The fourth proportional to 74.38, 111.72 and 71.43 is: 107.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.38 : 111.72 = 71.43 : x
  2. Step 2: Convert to fraction form
    74.38/111.72 = 71.43/x
  3. Step 3: Cross multiply
    74.38x = 111.72 × 71.43
  4. Step 4: Simplify right side
    74.38x = 7,979.24
  5. Step 5: Solve for x
    x = 7,979.24/74.38
  6. Step 6: Final answer
    x = 107.28

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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.