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Finding the Fourth Proportional to 198.80, 298.80 and 172.40

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Solution

The fourth proportional to 198.80, 298.80 and 172.40 is: 259.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.80 : 298.80 = 172.40 : x
  2. Step 2: Convert to fraction form
    198.80/298.80 = 172.40/x
  3. Step 3: Cross multiply
    198.80x = 298.80 × 172.40
  4. Step 4: Simplify right side
    198.80x = 51,513.12
  5. Step 5: Solve for x
    x = 51,513.12/198.80
  6. Step 6: Final answer
    x = 259.12

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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.