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Finding the Fourth Proportional to 1,238.13, 1,857.78 and 621.90

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Solution

The fourth proportional to 1,238.13, 1,857.78 and 621.90 is: 933.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.13 : 1,857.78 = 621.90 : x
  2. Step 2: Convert to fraction form
    1,238.13/1,857.78 = 621.90/x
  3. Step 3: Cross multiply
    1,238.13x = 1,857.78 × 621.90
  4. Step 4: Simplify right side
    1,238.13x = 1,155,353.38
  5. Step 5: Solve for x
    x = 1,155,353.38/1,238.13
  6. Step 6: Final answer
    x = 933.14

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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.