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Finding the Fourth Proportional to 457.12, 685.20 and 213.28

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Solution

The fourth proportional to 457.12, 685.20 and 213.28 is: 319.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    457.12 : 685.20 = 213.28 : x
  2. Step 2: Convert to fraction form
    457.12/685.20 = 213.28/x
  3. Step 3: Cross multiply
    457.12x = 685.20 × 213.28
  4. Step 4: Simplify right side
    457.12x = 146,139.46
  5. Step 5: Solve for x
    x = 146,139.46/457.12
  6. Step 6: Final answer
    x = 319.70

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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.