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Finding the Fourth Proportional to 485.76, 669.72 and 311.04

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Solution

The fourth proportional to 485.76, 669.72 and 311.04 is: 428.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.76 : 669.72 = 311.04 : x
  2. Step 2: Convert to fraction form
    485.76/669.72 = 311.04/x
  3. Step 3: Cross multiply
    485.76x = 669.72 × 311.04
  4. Step 4: Simplify right side
    485.76x = 208,309.71
  5. Step 5: Solve for x
    x = 208,309.71/485.76
  6. Step 6: Final answer
    x = 428.83

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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.