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Finding the Fourth Proportional to 908.05, 1,253.57 and 642.70

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Solution

The fourth proportional to 908.05, 1,253.57 and 642.70 is: 887.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.05 : 1,253.57 = 642.70 : x
  2. Step 2: Convert to fraction form
    908.05/1,253.57 = 642.70/x
  3. Step 3: Cross multiply
    908.05x = 1,253.57 × 642.70
  4. Step 4: Simplify right side
    908.05x = 805,673.82
  5. Step 5: Solve for x
    x = 805,673.82/908.05
  6. Step 6: Final answer
    x = 887.26

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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.