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Finding the Fourth Proportional to 305.76, 421.80 and 189.42

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Solution

The fourth proportional to 305.76, 421.80 and 189.42 is: 261.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.76 : 421.80 = 189.42 : x
  2. Step 2: Convert to fraction form
    305.76/421.80 = 189.42/x
  3. Step 3: Cross multiply
    305.76x = 421.80 × 189.42
  4. Step 4: Simplify right side
    305.76x = 79,897.36
  5. Step 5: Solve for x
    x = 79,897.36/305.76
  6. Step 6: Final answer
    x = 261.31

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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.