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Finding the Fourth Proportional to 458.21, 687.83 and 428.47

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Solution

The fourth proportional to 458.21, 687.83 and 428.47 is: 643.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.21 : 687.83 = 428.47 : x
  2. Step 2: Convert to fraction form
    458.21/687.83 = 428.47/x
  3. Step 3: Cross multiply
    458.21x = 687.83 × 428.47
  4. Step 4: Simplify right side
    458.21x = 294,710.66
  5. Step 5: Solve for x
    x = 294,710.66/458.21
  6. Step 6: Final answer
    x = 643.17

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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.