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Finding the Fourth Proportional to 1,391.38, 2,086.41 and 513.60

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Solution

The fourth proportional to 1,391.38, 2,086.41 and 513.60 is: 770.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.38 : 2,086.41 = 513.60 : x
  2. Step 2: Convert to fraction form
    1,391.38/2,086.41 = 513.60/x
  3. Step 3: Cross multiply
    1,391.38x = 2,086.41 × 513.60
  4. Step 4: Simplify right side
    1,391.38x = 1,071,569.74
  5. Step 5: Solve for x
    x = 1,071,569.74/1,391.38
  6. Step 6: Final answer
    x = 770.15

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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.