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Finding the Fourth Proportional to 261.96, 393.16 and 221.08

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Solution

The fourth proportional to 261.96, 393.16 and 221.08 is: 331.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.96 : 393.16 = 221.08 : x
  2. Step 2: Convert to fraction form
    261.96/393.16 = 221.08/x
  3. Step 3: Cross multiply
    261.96x = 393.16 × 221.08
  4. Step 4: Simplify right side
    261.96x = 86,919.81
  5. Step 5: Solve for x
    x = 86,919.81/261.96
  6. Step 6: Final answer
    x = 331.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.