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Finding the Fourth Proportional to 305.85, 421.91 and 189.39

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Solution

The fourth proportional to 305.85, 421.91 and 189.39 is: 261.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.85 : 421.91 = 189.39 : x
  2. Step 2: Convert to fraction form
    305.85/421.91 = 189.39/x
  3. Step 3: Cross multiply
    305.85x = 421.91 × 189.39
  4. Step 4: Simplify right side
    305.85x = 79,904.59
  5. Step 5: Solve for x
    x = 79,904.59/305.85
  6. Step 6: Final answer
    x = 261.25

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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.