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Finding the Fourth Proportional to 309.90, 427.32 and 211.71

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Solution

The fourth proportional to 309.90, 427.32 and 211.71 is: 291.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.90 : 427.32 = 211.71 : x
  2. Step 2: Convert to fraction form
    309.90/427.32 = 211.71/x
  3. Step 3: Cross multiply
    309.90x = 427.32 × 211.71
  4. Step 4: Simplify right side
    309.90x = 90,467.92
  5. Step 5: Solve for x
    x = 90,467.92/309.90
  6. Step 6: Final answer
    x = 291.93

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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.