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Finding the Fourth Proportional to 140.11, 210.18 and 78.81

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Solution

The fourth proportional to 140.11, 210.18 and 78.81 is: 118.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.11 : 210.18 = 78.81 : x
  2. Step 2: Convert to fraction form
    140.11/210.18 = 78.81/x
  3. Step 3: Cross multiply
    140.11x = 210.18 × 78.81
  4. Step 4: Simplify right side
    140.11x = 16,563.13
  5. Step 5: Solve for x
    x = 16,563.13/140.11
  6. Step 6: Final answer
    x = 118.21

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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.