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Finding the Fourth Proportional to 1,128.69, 1,693.44 and 642.69

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Solution

The fourth proportional to 1,128.69, 1,693.44 and 642.69 is: 964.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.69 : 1,693.44 = 642.69 : x
  2. Step 2: Convert to fraction form
    1,128.69/1,693.44 = 642.69/x
  3. Step 3: Cross multiply
    1,128.69x = 1,693.44 × 642.69
  4. Step 4: Simplify right side
    1,128.69x = 1,088,356.95
  5. Step 5: Solve for x
    x = 1,088,356.95/1,128.69
  6. Step 6: Final answer
    x = 964.27

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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.