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Finding the Fourth Proportional to 199.40, 299.06 and 85.40

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Solution

The fourth proportional to 199.40, 299.06 and 85.40 is: 128.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.40 : 299.06 = 85.40 : x
  2. Step 2: Convert to fraction form
    199.40/299.06 = 85.40/x
  3. Step 3: Cross multiply
    199.40x = 299.06 × 85.40
  4. Step 4: Simplify right side
    199.40x = 25,539.72
  5. Step 5: Solve for x
    x = 25,539.72/199.40
  6. Step 6: Final answer
    x = 128.08

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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.