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Finding the Fourth Proportional to 289.78, 436.39 and 261.22

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Solution

The fourth proportional to 289.78, 436.39 and 261.22 is: 393.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.78 : 436.39 = 261.22 : x
  2. Step 2: Convert to fraction form
    289.78/436.39 = 261.22/x
  3. Step 3: Cross multiply
    289.78x = 436.39 × 261.22
  4. Step 4: Simplify right side
    289.78x = 113,993.80
  5. Step 5: Solve for x
    x = 113,993.80/289.78
  6. Step 6: Final answer
    x = 393.38

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.