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Finding the Fourth Proportional to 1,128.12, 1,691.65 and 659.73

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Solution

The fourth proportional to 1,128.12, 1,691.65 and 659.73 is: 989.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.12 : 1,691.65 = 659.73 : x
  2. Step 2: Convert to fraction form
    1,128.12/1,691.65 = 659.73/x
  3. Step 3: Cross multiply
    1,128.12x = 1,691.65 × 659.73
  4. Step 4: Simplify right side
    1,128.12x = 1,116,028.05
  5. Step 5: Solve for x
    x = 1,116,028.05/1,128.12
  6. Step 6: Final answer
    x = 989.28

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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.