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Finding the Fourth Proportional to 390.84, 539.42 and 378.02

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Solution

The fourth proportional to 390.84, 539.42 and 378.02 is: 521.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.84 : 539.42 = 378.02 : x
  2. Step 2: Convert to fraction form
    390.84/539.42 = 378.02/x
  3. Step 3: Cross multiply
    390.84x = 539.42 × 378.02
  4. Step 4: Simplify right side
    390.84x = 203,913.13
  5. Step 5: Solve for x
    x = 203,913.13/390.84
  6. Step 6: Final answer
    x = 521.74

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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.