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Finding the Fourth Proportional to 305.70, 421.86 and 189.20

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Solution

The fourth proportional to 305.70, 421.86 and 189.20 is: 261.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.70 : 421.86 = 189.20 : x
  2. Step 2: Convert to fraction form
    305.70/421.86 = 189.20/x
  3. Step 3: Cross multiply
    305.70x = 421.86 × 189.20
  4. Step 4: Simplify right side
    305.70x = 79,813.80
  5. Step 5: Solve for x
    x = 79,813.80/305.70
  6. Step 6: Final answer
    x = 261.09

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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.