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Finding the Fourth Proportional to 199.85, 299.78 and 78.14

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Solution

The fourth proportional to 199.85, 299.78 and 78.14 is: 117.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.85 : 299.78 = 78.14 : x
  2. Step 2: Convert to fraction form
    199.85/299.78 = 78.14/x
  3. Step 3: Cross multiply
    199.85x = 299.78 × 78.14
  4. Step 4: Simplify right side
    199.85x = 23,424.81
  5. Step 5: Solve for x
    x = 23,424.81/199.85
  6. Step 6: Final answer
    x = 117.21

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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.