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Finding the Fourth Proportional to 485.57, 669.81 and 308.21

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Solution

The fourth proportional to 485.57, 669.81 and 308.21 is: 425.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.57 : 669.81 = 308.21 : x
  2. Step 2: Convert to fraction form
    485.57/669.81 = 308.21/x
  3. Step 3: Cross multiply
    485.57x = 669.81 × 308.21
  4. Step 4: Simplify right side
    485.57x = 206,442.14
  5. Step 5: Solve for x
    x = 206,442.14/485.57
  6. Step 6: Final answer
    x = 425.15

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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.