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Finding the Fourth Proportional to 485.47, 669.68 and 289.05

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Solution

The fourth proportional to 485.47, 669.68 and 289.05 is: 398.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.47 : 669.68 = 289.05 : x
  2. Step 2: Convert to fraction form
    485.47/669.68 = 289.05/x
  3. Step 3: Cross multiply
    485.47x = 669.68 × 289.05
  4. Step 4: Simplify right side
    485.47x = 193,566.21
  5. Step 5: Solve for x
    x = 193,566.21/485.47
  6. Step 6: Final answer
    x = 398.72

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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.