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Finding the Fourth Proportional to 309.70, 427.90 and 211.90

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Solution

The fourth proportional to 309.70, 427.90 and 211.90 is: 292.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.70 : 427.90 = 211.90 : x
  2. Step 2: Convert to fraction form
    309.70/427.90 = 211.90/x
  3. Step 3: Cross multiply
    309.70x = 427.90 × 211.90
  4. Step 4: Simplify right side
    309.70x = 90,672.01
  5. Step 5: Solve for x
    x = 90,672.01/309.70
  6. Step 6: Final answer
    x = 292.77

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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.