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Finding the Fourth Proportional to 199.85, 299.70 and 84.15

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Solution

The fourth proportional to 199.85, 299.70 and 84.15 is: 126.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.85 : 299.70 = 84.15 : x
  2. Step 2: Convert to fraction form
    199.85/299.70 = 84.15/x
  3. Step 3: Cross multiply
    199.85x = 299.70 × 84.15
  4. Step 4: Simplify right side
    199.85x = 25,219.76
  5. Step 5: Solve for x
    x = 25,219.76/199.85
  6. Step 6: Final answer
    x = 126.20

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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.