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Finding the Fourth Proportional to 1,287, 1,928.34 and 1,129.68

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Solution

The fourth proportional to 1,287, 1,928.34 and 1,129.68 is: 1,692.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287 : 1,928.34 = 1,129.68 : x
  2. Step 2: Convert to fraction form
    1,287/1,928.34 = 1,129.68/x
  3. Step 3: Cross multiply
    1,287x = 1,928.34 × 1,129.68
  4. Step 4: Simplify right side
    1,287x = 2,178,407.13
  5. Step 5: Solve for x
    x = 2,178,407.13/1,287
  6. Step 6: Final answer
    x = 1,692.62

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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.