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Finding the Fourth Proportional to 440.28, 656.85 and 428.76

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Solution

The fourth proportional to 440.28, 656.85 and 428.76 is: 639.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    440.28 : 656.85 = 428.76 : x
  2. Step 2: Convert to fraction form
    440.28/656.85 = 428.76/x
  3. Step 3: Cross multiply
    440.28x = 656.85 × 428.76
  4. Step 4: Simplify right side
    440.28x = 281,631.01
  5. Step 5: Solve for x
    x = 281,631.01/440.28
  6. Step 6: Final answer
    x = 639.66

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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.