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Finding the Fourth Proportional to 678.78, 1,018.05 and 216.57

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Solution

The fourth proportional to 678.78, 1,018.05 and 216.57 is: 324.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.78 : 1,018.05 = 216.57 : x
  2. Step 2: Convert to fraction form
    678.78/1,018.05 = 216.57/x
  3. Step 3: Cross multiply
    678.78x = 1,018.05 × 216.57
  4. Step 4: Simplify right side
    678.78x = 220,479.09
  5. Step 5: Solve for x
    x = 220,479.09/678.78
  6. Step 6: Final answer
    x = 324.82

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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.