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Finding the Fourth Proportional to 315.17, 434.20 and 221.75

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Solution

The fourth proportional to 315.17, 434.20 and 221.75 is: 305.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    315.17 : 434.20 = 221.75 : x
  2. Step 2: Convert to fraction form
    315.17/434.20 = 221.75/x
  3. Step 3: Cross multiply
    315.17x = 434.20 × 221.75
  4. Step 4: Simplify right side
    315.17x = 96,283.85
  5. Step 5: Solve for x
    x = 96,283.85/315.17
  6. Step 6: Final answer
    x = 305.50

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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.