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Finding the Fourth Proportional to 458.31, 687.99 and 428.58

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Solution

The fourth proportional to 458.31, 687.99 and 428.58 is: 643.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.31 : 687.99 = 428.58 : x
  2. Step 2: Convert to fraction form
    458.31/687.99 = 428.58/x
  3. Step 3: Cross multiply
    458.31x = 687.99 × 428.58
  4. Step 4: Simplify right side
    458.31x = 294,858.75
  5. Step 5: Solve for x
    x = 294,858.75/458.31
  6. Step 6: Final answer
    x = 643.36

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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.