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Finding the Fourth Proportional to 1,128.74, 1,690.14 and 868.12

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Solution

The fourth proportional to 1,128.74, 1,690.14 and 868.12 is: 1,299.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.74 : 1,690.14 = 868.12 : x
  2. Step 2: Convert to fraction form
    1,128.74/1,690.14 = 868.12/x
  3. Step 3: Cross multiply
    1,128.74x = 1,690.14 × 868.12
  4. Step 4: Simplify right side
    1,128.74x = 1,467,240.93
  5. Step 5: Solve for x
    x = 1,467,240.93/1,128.74
  6. Step 6: Final answer
    x = 1,299.90

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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.