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Finding the Fourth Proportional to 199.70, 299.43 and 77.90

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Solution

The fourth proportional to 199.70, 299.43 and 77.90 is: 116.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.70 : 299.43 = 77.90 : x
  2. Step 2: Convert to fraction form
    199.70/299.43 = 77.90/x
  3. Step 3: Cross multiply
    199.70x = 299.43 × 77.90
  4. Step 4: Simplify right side
    199.70x = 23,325.60
  5. Step 5: Solve for x
    x = 23,325.60/199.70
  6. Step 6: Final answer
    x = 116.80

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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.