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Finding the Fourth Proportional to 458.80, 688.20 and 428.20

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Solution

The fourth proportional to 458.80, 688.20 and 428.20 is: 642.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    458.80 : 688.20 = 428.20 : x
  2. Step 2: Convert to fraction form
    458.80/688.20 = 428.20/x
  3. Step 3: Cross multiply
    458.80x = 688.20 × 428.20
  4. Step 4: Simplify right side
    458.80x = 294,687.24
  5. Step 5: Solve for x
    x = 294,687.24/458.80
  6. Step 6: Final answer
    x = 642.30

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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.