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Finding the Fourth Proportional to 485.35, 669.78 and 286.31

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Solution

The fourth proportional to 485.35, 669.78 and 286.31 is: 395.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.35 : 669.78 = 286.31 : x
  2. Step 2: Convert to fraction form
    485.35/669.78 = 286.31/x
  3. Step 3: Cross multiply
    485.35x = 669.78 × 286.31
  4. Step 4: Simplify right side
    485.35x = 191,766.39
  5. Step 5: Solve for x
    x = 191,766.39/485.35
  6. Step 6: Final answer
    x = 395.11

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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.