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Finding the Fourth Proportional to 485.40, 727.80 and 311.76

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Solution

The fourth proportional to 485.40, 727.80 and 311.76 is: 467.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.40 : 727.80 = 311.76 : x
  2. Step 2: Convert to fraction form
    485.40/727.80 = 311.76/x
  3. Step 3: Cross multiply
    485.40x = 727.80 × 311.76
  4. Step 4: Simplify right side
    485.40x = 226,898.93
  5. Step 5: Solve for x
    x = 226,898.93/485.40
  6. Step 6: Final answer
    x = 467.45

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.