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Finding the Fourth Proportional to 485.12, 669.36 and 310.72

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Solution

The fourth proportional to 485.12, 669.36 and 310.72 is: 428.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.12 : 669.36 = 310.72 : x
  2. Step 2: Convert to fraction form
    485.12/669.36 = 310.72/x
  3. Step 3: Cross multiply
    485.12x = 669.36 × 310.72
  4. Step 4: Simplify right side
    485.12x = 207,983.54
  5. Step 5: Solve for x
    x = 207,983.54/485.12
  6. Step 6: Final answer
    x = 428.73

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.