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Finding the Fourth Proportional to 309.79, 427.43 and 211.58

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Solution

The fourth proportional to 309.79, 427.43 and 211.58 is: 291.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.79 : 427.43 = 211.58 : x
  2. Step 2: Convert to fraction form
    309.79/427.43 = 211.58/x
  3. Step 3: Cross multiply
    309.79x = 427.43 × 211.58
  4. Step 4: Simplify right side
    309.79x = 90,432.44
  5. Step 5: Solve for x
    x = 90,432.44/309.79
  6. Step 6: Final answer
    x = 291.92

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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.