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Finding the Fourth Proportional to 678.85, 1,018.19 and 216.68

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Solution

The fourth proportional to 678.85, 1,018.19 and 216.68 is: 324.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.85 : 1,018.19 = 216.68 : x
  2. Step 2: Convert to fraction form
    678.85/1,018.19 = 216.68/x
  3. Step 3: Cross multiply
    678.85x = 1,018.19 × 216.68
  4. Step 4: Simplify right side
    678.85x = 220,616.86
  5. Step 5: Solve for x
    x = 220,616.86/678.85
  6. Step 6: Final answer
    x = 324.99

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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.