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Finding the Fourth Proportional to 885.40, 1,221.78 and 553.60

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Solution

The fourth proportional to 885.40, 1,221.78 and 553.60 is: 763.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    885.40 : 1,221.78 = 553.60 : x
  2. Step 2: Convert to fraction form
    885.40/1,221.78 = 553.60/x
  3. Step 3: Cross multiply
    885.40x = 1,221.78 × 553.60
  4. Step 4: Simplify right side
    885.40x = 676,377.41
  5. Step 5: Solve for x
    x = 676,377.41/885.40
  6. Step 6: Final answer
    x = 763.92

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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.