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Finding the Fourth Proportional to 428.60, 641.99 and 312.48

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Solution

The fourth proportional to 428.60, 641.99 and 312.48 is: 468.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.60 : 641.99 = 312.48 : x
  2. Step 2: Convert to fraction form
    428.60/641.99 = 312.48/x
  3. Step 3: Cross multiply
    428.60x = 641.99 × 312.48
  4. Step 4: Simplify right side
    428.60x = 200,607.47
  5. Step 5: Solve for x
    x = 200,607.47/428.60
  6. Step 6: Final answer
    x = 468.06

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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.