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Finding the Fourth Proportional to 321.28, 478.12 and 309.76

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Solution

The fourth proportional to 321.28, 478.12 and 309.76 is: 460.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.28 : 478.12 = 309.76 : x
  2. Step 2: Convert to fraction form
    321.28/478.12 = 309.76/x
  3. Step 3: Cross multiply
    321.28x = 478.12 × 309.76
  4. Step 4: Simplify right side
    321.28x = 148,102.45
  5. Step 5: Solve for x
    x = 148,102.45/321.28
  6. Step 6: Final answer
    x = 460.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.