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Finding the Fourth Proportional to 109.21, 164.45 and 78.98

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Solution

The fourth proportional to 109.21, 164.45 and 78.98 is: 118.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.21 : 164.45 = 78.98 : x
  2. Step 2: Convert to fraction form
    109.21/164.45 = 78.98/x
  3. Step 3: Cross multiply
    109.21x = 164.45 × 78.98
  4. Step 4: Simplify right side
    109.21x = 12,988.97
  5. Step 5: Solve for x
    x = 12,988.97/109.21
  6. Step 6: Final answer
    x = 118.94

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.