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Finding the Fourth Proportional to 306.90, 423.45 and 213.75

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Solution

The fourth proportional to 306.90, 423.45 and 213.75 is: 294.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.90 : 423.45 = 213.75 : x
  2. Step 2: Convert to fraction form
    306.90/423.45 = 213.75/x
  3. Step 3: Cross multiply
    306.90x = 423.45 × 213.75
  4. Step 4: Simplify right side
    306.90x = 90,512.44
  5. Step 5: Solve for x
    x = 90,512.44/306.90
  6. Step 6: Final answer
    x = 294.92

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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.