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Finding the Fourth Proportional to 1,128.74, 1,693.41 and 642.13

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Solution

The fourth proportional to 1,128.74, 1,693.41 and 642.13 is: 963.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.74 : 1,693.41 = 642.13 : x
  2. Step 2: Convert to fraction form
    1,128.74/1,693.41 = 642.13/x
  3. Step 3: Cross multiply
    1,128.74x = 1,693.41 × 642.13
  4. Step 4: Simplify right side
    1,128.74x = 1,087,382.72
  5. Step 5: Solve for x
    x = 1,087,382.72/1,128.74
  6. Step 6: Final answer
    x = 963.36

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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.