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Finding the Fourth Proportional to 309.66, 427.47 and 221.16

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Solution

The fourth proportional to 309.66, 427.47 and 221.16 is: 305.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.66 : 427.47 = 221.16 : x
  2. Step 2: Convert to fraction form
    309.66/427.47 = 221.16/x
  3. Step 3: Cross multiply
    309.66x = 427.47 × 221.16
  4. Step 4: Simplify right side
    309.66x = 94,539.27
  5. Step 5: Solve for x
    x = 94,539.27/309.66
  6. Step 6: Final answer
    x = 305.30

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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.