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Finding the Fourth Proportional to 140.49, 210.78 and 99.81

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Solution

The fourth proportional to 140.49, 210.78 and 99.81 is: 149.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.49 : 210.78 = 99.81 : x
  2. Step 2: Convert to fraction form
    140.49/210.78 = 99.81/x
  3. Step 3: Cross multiply
    140.49x = 210.78 × 99.81
  4. Step 4: Simplify right side
    140.49x = 21,037.95
  5. Step 5: Solve for x
    x = 21,037.95/140.49
  6. Step 6: Final answer
    x = 149.75

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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.