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Finding the Fourth Proportional to 309.88, 427.68 and 211.72

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Solution

The fourth proportional to 309.88, 427.68 and 211.72 is: 292.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.88 : 427.68 = 211.72 : x
  2. Step 2: Convert to fraction form
    309.88/427.68 = 211.72/x
  3. Step 3: Cross multiply
    309.88x = 427.68 × 211.72
  4. Step 4: Simplify right side
    309.88x = 90,548.41
  5. Step 5: Solve for x
    x = 90,548.41/309.88
  6. Step 6: Final answer
    x = 292.20

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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.