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Finding the Fourth Proportional to 685.65, 1,028.39 and 315.48

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Solution

The fourth proportional to 685.65, 1,028.39 and 315.48 is: 473.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.65 : 1,028.39 = 315.48 : x
  2. Step 2: Convert to fraction form
    685.65/1,028.39 = 315.48/x
  3. Step 3: Cross multiply
    685.65x = 1,028.39 × 315.48
  4. Step 4: Simplify right side
    685.65x = 324,434.90
  5. Step 5: Solve for x
    x = 324,434.90/685.65
  6. Step 6: Final answer
    x = 473.18

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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.