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Finding the Fourth Proportional to 821.21, 1,133.49 and 555.53

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Solution

The fourth proportional to 821.21, 1,133.49 and 555.53 is: 766.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.21 : 1,133.49 = 555.53 : x
  2. Step 2: Convert to fraction form
    821.21/1,133.49 = 555.53/x
  3. Step 3: Cross multiply
    821.21x = 1,133.49 × 555.53
  4. Step 4: Simplify right side
    821.21x = 629,687.70
  5. Step 5: Solve for x
    x = 629,687.70/821.21
  6. Step 6: Final answer
    x = 766.78

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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.