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Finding the Fourth Proportional to 816.11, 1,126.40 and 638.72

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Solution

The fourth proportional to 816.11, 1,126.40 and 638.72 is: 881.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.11 : 1,126.40 = 638.72 : x
  2. Step 2: Convert to fraction form
    816.11/1,126.40 = 638.72/x
  3. Step 3: Cross multiply
    816.11x = 1,126.40 × 638.72
  4. Step 4: Simplify right side
    816.11x = 719,445.38
  5. Step 5: Solve for x
    x = 719,445.38/816.11
  6. Step 6: Final answer
    x = 881.56

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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.