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Finding the Fourth Proportional to 781.38, 1,169.78 and 518.13

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Solution

The fourth proportional to 781.38, 1,169.78 and 518.13 is: 775.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.38 : 1,169.78 = 518.13 : x
  2. Step 2: Convert to fraction form
    781.38/1,169.78 = 518.13/x
  3. Step 3: Cross multiply
    781.38x = 1,169.78 × 518.13
  4. Step 4: Simplify right side
    781.38x = 606,095.52
  5. Step 5: Solve for x
    x = 606,095.52/781.38
  6. Step 6: Final answer
    x = 775.67

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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.