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Finding the Fourth Proportional to 109.47, 164.21 and 78.89

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Solution

The fourth proportional to 109.47, 164.21 and 78.89 is: 118.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.47 : 164.21 = 78.89 : x
  2. Step 2: Convert to fraction form
    109.47/164.21 = 78.89/x
  3. Step 3: Cross multiply
    109.47x = 164.21 × 78.89
  4. Step 4: Simplify right side
    109.47x = 12,954.54
  5. Step 5: Solve for x
    x = 12,954.54/109.47
  6. Step 6: Final answer
    x = 118.34

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.