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Finding the Fourth Proportional to 679.74, 1,018.87 and 486.78

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Solution

The fourth proportional to 679.74, 1,018.87 and 486.78 is: 729.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.74 : 1,018.87 = 486.78 : x
  2. Step 2: Convert to fraction form
    679.74/1,018.87 = 486.78/x
  3. Step 3: Cross multiply
    679.74x = 1,018.87 × 486.78
  4. Step 4: Simplify right side
    679.74x = 495,965.54
  5. Step 5: Solve for x
    x = 495,965.54/679.74
  6. Step 6: Final answer
    x = 729.64

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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.