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Finding the Fourth Proportional to 1,387.88, 1,915.26 and 798.40

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Solution

The fourth proportional to 1,387.88, 1,915.26 and 798.40 is: 1,101.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.88 : 1,915.26 = 798.40 : x
  2. Step 2: Convert to fraction form
    1,387.88/1,915.26 = 798.40/x
  3. Step 3: Cross multiply
    1,387.88x = 1,915.26 × 798.40
  4. Step 4: Simplify right side
    1,387.88x = 1,529,143.58
  5. Step 5: Solve for x
    x = 1,529,143.58/1,387.88
  6. Step 6: Final answer
    x = 1,101.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.