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Finding the Fourth Proportional to 919.85, 1,379.78 and 508.76

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Solution

The fourth proportional to 919.85, 1,379.78 and 508.76 is: 763.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.85 : 1,379.78 = 508.76 : x
  2. Step 2: Convert to fraction form
    919.85/1,379.78 = 508.76/x
  3. Step 3: Cross multiply
    919.85x = 1,379.78 × 508.76
  4. Step 4: Simplify right side
    919.85x = 701,976.87
  5. Step 5: Solve for x
    x = 701,976.87/919.85
  6. Step 6: Final answer
    x = 763.14

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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.