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Finding the Fourth Proportional to 393.72, 539.82 and 388.80

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Solution

The fourth proportional to 393.72, 539.82 and 388.80 is: 533.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.72 : 539.82 = 388.80 : x
  2. Step 2: Convert to fraction form
    393.72/539.82 = 388.80/x
  3. Step 3: Cross multiply
    393.72x = 539.82 × 388.80
  4. Step 4: Simplify right side
    393.72x = 209,882.02
  5. Step 5: Solve for x
    x = 209,882.02/393.72
  6. Step 6: Final answer
    x = 533.07

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.