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Finding the Fourth Proportional to 1,239.74, 1,859.90 and 418

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Solution

The fourth proportional to 1,239.74, 1,859.90 and 418 is: 627.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.74 : 1,859.90 = 418 : x
  2. Step 2: Convert to fraction form
    1,239.74/1,859.90 = 418/x
  3. Step 3: Cross multiply
    1,239.74x = 1,859.90 × 418
  4. Step 4: Simplify right side
    1,239.74x = 777,438.20
  5. Step 5: Solve for x
    x = 777,438.20/1,239.74
  6. Step 6: Final answer
    x = 627.10

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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.