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Finding the Fourth Proportional to 309.78, 427.67 and 191.78

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Solution

The fourth proportional to 309.78, 427.67 and 191.78 is: 264.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.78 : 427.67 = 191.78 : x
  2. Step 2: Convert to fraction form
    309.78/427.67 = 191.78/x
  3. Step 3: Cross multiply
    309.78x = 427.67 × 191.78
  4. Step 4: Simplify right side
    309.78x = 82,015.46
  5. Step 5: Solve for x
    x = 82,015.46/309.78
  6. Step 6: Final answer
    x = 264.75

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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.