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Finding the Fourth Proportional to 485.36, 669.85 and 308.40

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Solution

The fourth proportional to 485.36, 669.85 and 308.40 is: 425.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.36 : 669.85 = 308.40 : x
  2. Step 2: Convert to fraction form
    485.36/669.85 = 308.40/x
  3. Step 3: Cross multiply
    485.36x = 669.85 × 308.40
  4. Step 4: Simplify right side
    485.36x = 206,581.74
  5. Step 5: Solve for x
    x = 206,581.74/485.36
  6. Step 6: Final answer
    x = 425.63

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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.