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Finding the Fourth Proportional to 1,240.87, 1,860 and 418.86

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Solution

The fourth proportional to 1,240.87, 1,860 and 418.86 is: 627.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,240.87 : 1,860 = 418.86 : x
  2. Step 2: Convert to fraction form
    1,240.87/1,860 = 418.86/x
  3. Step 3: Cross multiply
    1,240.87x = 1,860 × 418.86
  4. Step 4: Simplify right side
    1,240.87x = 779,079.60
  5. Step 5: Solve for x
    x = 779,079.60/1,240.87
  6. Step 6: Final answer
    x = 627.85

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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.