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Finding the Fourth Proportional to 660.31, 990.46 and 429.76

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Solution

The fourth proportional to 660.31, 990.46 and 429.76 is: 644.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.31 : 990.46 = 429.76 : x
  2. Step 2: Convert to fraction form
    660.31/990.46 = 429.76/x
  3. Step 3: Cross multiply
    660.31x = 990.46 × 429.76
  4. Step 4: Simplify right side
    660.31x = 425,661.86
  5. Step 5: Solve for x
    x = 425,661.86/660.31
  6. Step 6: Final answer
    x = 644.64

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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.