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Finding the Fourth Proportional to 189.80, 261.93 and 105.78

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Solution

The fourth proportional to 189.80, 261.93 and 105.78 is: 145.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.80 : 261.93 = 105.78 : x
  2. Step 2: Convert to fraction form
    189.80/261.93 = 105.78/x
  3. Step 3: Cross multiply
    189.80x = 261.93 × 105.78
  4. Step 4: Simplify right side
    189.80x = 27,706.86
  5. Step 5: Solve for x
    x = 27,706.86/189.80
  6. Step 6: Final answer
    x = 145.98

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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.