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Finding the Fourth Proportional to 105.65, 158.30 and 54.21

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Solution

The fourth proportional to 105.65, 158.30 and 54.21 is: 81.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.65 : 158.30 = 54.21 : x
  2. Step 2: Convert to fraction form
    105.65/158.30 = 54.21/x
  3. Step 3: Cross multiply
    105.65x = 158.30 × 54.21
  4. Step 4: Simplify right side
    105.65x = 8,581.44
  5. Step 5: Solve for x
    x = 8,581.44/105.65
  6. Step 6: Final answer
    x = 81.23

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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.