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Finding the Fourth Proportional to 309.76, 427.29 and 211.55

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Solution

The fourth proportional to 309.76, 427.29 and 211.55 is: 291.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.76 : 427.29 = 211.55 : x
  2. Step 2: Convert to fraction form
    309.76/427.29 = 211.55/x
  3. Step 3: Cross multiply
    309.76x = 427.29 × 211.55
  4. Step 4: Simplify right side
    309.76x = 90,393.20
  5. Step 5: Solve for x
    x = 90,393.20/309.76
  6. Step 6: Final answer
    x = 291.82

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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.