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Finding the Fourth Proportional to 392.40, 542 and 261.20

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Solution

The fourth proportional to 392.40, 542 and 261.20 is: 360.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.40 : 542 = 261.20 : x
  2. Step 2: Convert to fraction form
    392.40/542 = 261.20/x
  3. Step 3: Cross multiply
    392.40x = 542 × 261.20
  4. Step 4: Simplify right side
    392.40x = 141,570.40
  5. Step 5: Solve for x
    x = 141,570.40/392.40
  6. Step 6: Final answer
    x = 360.78

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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.