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Finding the Fourth Proportional to 655.80, 905.13 and 393.99

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Solution

The fourth proportional to 655.80, 905.13 and 393.99 is: 543.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    655.80 : 905.13 = 393.99 : x
  2. Step 2: Convert to fraction form
    655.80/905.13 = 393.99/x
  3. Step 3: Cross multiply
    655.80x = 905.13 × 393.99
  4. Step 4: Simplify right side
    655.80x = 356,612.17
  5. Step 5: Solve for x
    x = 356,612.17/655.80
  6. Step 6: Final answer
    x = 543.78

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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.