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Finding the Fourth Proportional to 678.38, 1,016.20 and 312.66

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Solution

The fourth proportional to 678.38, 1,016.20 and 312.66 is: 468.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.38 : 1,016.20 = 312.66 : x
  2. Step 2: Convert to fraction form
    678.38/1,016.20 = 312.66/x
  3. Step 3: Cross multiply
    678.38x = 1,016.20 × 312.66
  4. Step 4: Simplify right side
    678.38x = 317,725.48
  5. Step 5: Solve for x
    x = 317,725.48/678.38
  6. Step 6: Final answer
    x = 468.36

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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.