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Finding the Fourth Proportional to 386.21, 578.90 and 261.13

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Solution

The fourth proportional to 386.21, 578.90 and 261.13 is: 391.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.21 : 578.90 = 261.13 : x
  2. Step 2: Convert to fraction form
    386.21/578.90 = 261.13/x
  3. Step 3: Cross multiply
    386.21x = 578.90 × 261.13
  4. Step 4: Simplify right side
    386.21x = 151,163.96
  5. Step 5: Solve for x
    x = 151,163.96/386.21
  6. Step 6: Final answer
    x = 391.41

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.