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Finding the Fourth Proportional to 305.78, 421.40 and 222.65

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Solution

The fourth proportional to 305.78, 421.40 and 222.65 is: 306.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.78 : 421.40 = 222.65 : x
  2. Step 2: Convert to fraction form
    305.78/421.40 = 222.65/x
  3. Step 3: Cross multiply
    305.78x = 421.40 × 222.65
  4. Step 4: Simplify right side
    305.78x = 93,824.74
  5. Step 5: Solve for x
    x = 93,824.74/305.78
  6. Step 6: Final answer
    x = 306.84

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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.