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Finding the Fourth Proportional to 739.28, 1,020.18 and 428.72

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Solution

The fourth proportional to 739.28, 1,020.18 and 428.72 is: 591.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    739.28 : 1,020.18 = 428.72 : x
  2. Step 2: Convert to fraction form
    739.28/1,020.18 = 428.72/x
  3. Step 3: Cross multiply
    739.28x = 1,020.18 × 428.72
  4. Step 4: Simplify right side
    739.28x = 437,371.57
  5. Step 5: Solve for x
    x = 437,371.57/739.28
  6. Step 6: Final answer
    x = 591.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.