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Finding the Fourth Proportional to 907.89, 1,251.36 and 642.45

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Solution

The fourth proportional to 907.89, 1,251.36 and 642.45 is: 885.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    907.89 : 1,251.36 = 642.45 : x
  2. Step 2: Convert to fraction form
    907.89/1,251.36 = 642.45/x
  3. Step 3: Cross multiply
    907.89x = 1,251.36 × 642.45
  4. Step 4: Simplify right side
    907.89x = 803,936.23
  5. Step 5: Solve for x
    x = 803,936.23/907.89
  6. Step 6: Final answer
    x = 885.50

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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.