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Finding the Fourth Proportional to 839.88, 1,158.39 and 642.96

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Solution

The fourth proportional to 839.88, 1,158.39 and 642.96 is: 886.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.88 : 1,158.39 = 642.96 : x
  2. Step 2: Convert to fraction form
    839.88/1,158.39 = 642.96/x
  3. Step 3: Cross multiply
    839.88x = 1,158.39 × 642.96
  4. Step 4: Simplify right side
    839.88x = 744,798.43
  5. Step 5: Solve for x
    x = 744,798.43/839.88
  6. Step 6: Final answer
    x = 886.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.