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Finding the Fourth Proportional to 1,387, 2,078.88 and 770.41

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Solution

The fourth proportional to 1,387, 2,078.88 and 770.41 is: 1,154.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387 : 2,078.88 = 770.41 : x
  2. Step 2: Convert to fraction form
    1,387/2,078.88 = 770.41/x
  3. Step 3: Cross multiply
    1,387x = 2,078.88 × 770.41
  4. Step 4: Simplify right side
    1,387x = 1,601,589.94
  5. Step 5: Solve for x
    x = 1,601,589.94/1,387
  6. Step 6: Final answer
    x = 1,154.72

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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.