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Finding the Fourth Proportional to 487.63, 728.02 and 428.85

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Solution

The fourth proportional to 487.63, 728.02 and 428.85 is: 640.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    487.63 : 728.02 = 428.85 : x
  2. Step 2: Convert to fraction form
    487.63/728.02 = 428.85/x
  3. Step 3: Cross multiply
    487.63x = 728.02 × 428.85
  4. Step 4: Simplify right side
    487.63x = 312,211.38
  5. Step 5: Solve for x
    x = 312,211.38/487.63
  6. Step 6: Final answer
    x = 640.26

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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.