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Finding the Fourth Proportional to 309.72, 427.20 and 211.32

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Solution

The fourth proportional to 309.72, 427.20 and 211.32 is: 291.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.72 : 427.20 = 211.32 : x
  2. Step 2: Convert to fraction form
    309.72/427.20 = 211.32/x
  3. Step 3: Cross multiply
    309.72x = 427.20 × 211.32
  4. Step 4: Simplify right side
    309.72x = 90,275.90
  5. Step 5: Solve for x
    x = 90,275.90/309.72
  6. Step 6: Final answer
    x = 291.48

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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.