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Finding the Fourth Proportional to 309.47, 427.20 and 221.13

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Solution

The fourth proportional to 309.47, 427.20 and 221.13 is: 305.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.47 : 427.20 = 221.13 : x
  2. Step 2: Convert to fraction form
    309.47/427.20 = 221.13/x
  3. Step 3: Cross multiply
    309.47x = 427.20 × 221.13
  4. Step 4: Simplify right side
    309.47x = 94,466.74
  5. Step 5: Solve for x
    x = 94,466.74/309.47
  6. Step 6: Final answer
    x = 305.26

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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.