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Finding the Fourth Proportional to 1,005, 1,386.90 and 591

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Solution

The fourth proportional to 1,005, 1,386.90 and 591 is: 815.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005 : 1,386.90 = 591 : x
  2. Step 2: Convert to fraction form
    1,005/1,386.90 = 591/x
  3. Step 3: Cross multiply
    1,005x = 1,386.90 × 591
  4. Step 4: Simplify right side
    1,005x = 819,657.90
  5. Step 5: Solve for x
    x = 819,657.90/1,005
  6. Step 6: Final answer
    x = 815.58

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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.