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Finding the Fourth Proportional to 105.84, 158.64 and 81.72

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Solution

The fourth proportional to 105.84, 158.64 and 81.72 is: 122.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.84 : 158.64 = 81.72 : x
  2. Step 2: Convert to fraction form
    105.84/158.64 = 81.72/x
  3. Step 3: Cross multiply
    105.84x = 158.64 × 81.72
  4. Step 4: Simplify right side
    105.84x = 12,964.06
  5. Step 5: Solve for x
    x = 12,964.06/105.84
  6. Step 6: Final answer
    x = 122.49

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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.