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Finding the Fourth Proportional to 679.23, 1,018.85 and 386.57

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Solution

The fourth proportional to 679.23, 1,018.85 and 386.57 is: 579.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.23 : 1,018.85 = 386.57 : x
  2. Step 2: Convert to fraction form
    679.23/1,018.85 = 386.57/x
  3. Step 3: Cross multiply
    679.23x = 1,018.85 × 386.57
  4. Step 4: Simplify right side
    679.23x = 393,857.46
  5. Step 5: Solve for x
    x = 393,857.46/679.23
  6. Step 6: Final answer
    x = 579.86

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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.