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Finding the Fourth Proportional to 678.89, 1,018.35 and 216.69

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Solution

The fourth proportional to 678.89, 1,018.35 and 216.69 is: 325.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.89 : 1,018.35 = 216.69 : x
  2. Step 2: Convert to fraction form
    678.89/1,018.35 = 216.69/x
  3. Step 3: Cross multiply
    678.89x = 1,018.35 × 216.69
  4. Step 4: Simplify right side
    678.89x = 220,666.26
  5. Step 5: Solve for x
    x = 220,666.26/678.89
  6. Step 6: Final answer
    x = 325.04

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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.