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Finding the Fourth Proportional to 199.78, 275.63 and 121.12

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Solution

The fourth proportional to 199.78, 275.63 and 121.12 is: 167.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    199.78 : 275.63 = 121.12 : x
  2. Step 2: Convert to fraction form
    199.78/275.63 = 121.12/x
  3. Step 3: Cross multiply
    199.78x = 275.63 × 121.12
  4. Step 4: Simplify right side
    199.78x = 33,384.31
  5. Step 5: Solve for x
    x = 33,384.31/199.78
  6. Step 6: Final answer
    x = 167.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.