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Finding the Fourth Proportional to 679.72, 1,016.78 and 621.52

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Solution

The fourth proportional to 679.72, 1,016.78 and 621.52 is: 929.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.72 : 1,016.78 = 621.52 : x
  2. Step 2: Convert to fraction form
    679.72/1,016.78 = 621.52/x
  3. Step 3: Cross multiply
    679.72x = 1,016.78 × 621.52
  4. Step 4: Simplify right side
    679.72x = 631,949.11
  5. Step 5: Solve for x
    x = 631,949.11/679.72
  6. Step 6: Final answer
    x = 929.72

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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.