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Finding the Fourth Proportional to 485.50, 669.96 and 289

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Solution

The fourth proportional to 485.50, 669.96 and 289 is: 398.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.50 : 669.96 = 289 : x
  2. Step 2: Convert to fraction form
    485.50/669.96 = 289/x
  3. Step 3: Cross multiply
    485.50x = 669.96 × 289
  4. Step 4: Simplify right side
    485.50x = 193,618.44
  5. Step 5: Solve for x
    x = 193,618.44/485.50
  6. Step 6: Final answer
    x = 398.80

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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.