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Finding the Fourth Proportional to 877.78, 1,211.81 and 641.49

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Solution

The fourth proportional to 877.78, 1,211.81 and 641.49 is: 885.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.78 : 1,211.81 = 641.49 : x
  2. Step 2: Convert to fraction form
    877.78/1,211.81 = 641.49/x
  3. Step 3: Cross multiply
    877.78x = 1,211.81 × 641.49
  4. Step 4: Simplify right side
    877.78x = 777,364.00
  5. Step 5: Solve for x
    x = 777,364.00/877.78
  6. Step 6: Final answer
    x = 885.60

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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.