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Finding the Fourth Proportional to 1,387.71, 1,915.02 and 766.71

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Solution

The fourth proportional to 1,387.71, 1,915.02 and 766.71 is: 1,058.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.71 : 1,915.02 = 766.71 : x
  2. Step 2: Convert to fraction form
    1,387.71/1,915.02 = 766.71/x
  3. Step 3: Cross multiply
    1,387.71x = 1,915.02 × 766.71
  4. Step 4: Simplify right side
    1,387.71x = 1,468,264.98
  5. Step 5: Solve for x
    x = 1,468,264.98/1,387.71
  6. Step 6: Final answer
    x = 1,058.05

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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.