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Finding the Fourth Proportional to 428.47, 643 and 320.53

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Solution

The fourth proportional to 428.47, 643 and 320.53 is: 481.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.47 : 643 = 320.53 : x
  2. Step 2: Convert to fraction form
    428.47/643 = 320.53/x
  3. Step 3: Cross multiply
    428.47x = 643 × 320.53
  4. Step 4: Simplify right side
    428.47x = 206,100.79
  5. Step 5: Solve for x
    x = 206,100.79/428.47
  6. Step 6: Final answer
    x = 481.02

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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.