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Finding the Fourth Proportional to 305.76, 421.80 and 199.42

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Solution

The fourth proportional to 305.76, 421.80 and 199.42 is: 275.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.76 : 421.80 = 199.42 : x
  2. Step 2: Convert to fraction form
    305.76/421.80 = 199.42/x
  3. Step 3: Cross multiply
    305.76x = 421.80 × 199.42
  4. Step 4: Simplify right side
    305.76x = 84,115.36
  5. Step 5: Solve for x
    x = 84,115.36/305.76
  6. Step 6: Final answer
    x = 275.10

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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.