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Finding the Fourth Proportional to 908.82, 1,253.62 and 642.85

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Solution

The fourth proportional to 908.82, 1,253.62 and 642.85 is: 886.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.82 : 1,253.62 = 642.85 : x
  2. Step 2: Convert to fraction form
    908.82/1,253.62 = 642.85/x
  3. Step 3: Cross multiply
    908.82x = 1,253.62 × 642.85
  4. Step 4: Simplify right side
    908.82x = 805,889.62
  5. Step 5: Solve for x
    x = 805,889.62/908.82
  6. Step 6: Final answer
    x = 886.74

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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.