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Finding the Fourth Proportional to 909.49, 1,253.76 and 643.11

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Solution

The fourth proportional to 909.49, 1,253.76 and 643.11 is: 886.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.49 : 1,253.76 = 643.11 : x
  2. Step 2: Convert to fraction form
    909.49/1,253.76 = 643.11/x
  3. Step 3: Cross multiply
    909.49x = 1,253.76 × 643.11
  4. Step 4: Simplify right side
    909.49x = 806,305.59
  5. Step 5: Solve for x
    x = 806,305.59/909.49
  6. Step 6: Final answer
    x = 886.55

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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.