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Finding the Fourth Proportional to 154.78, 213.54 and 99.45

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Solution

The fourth proportional to 154.78, 213.54 and 99.45 is: 137.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.78 : 213.54 = 99.45 : x
  2. Step 2: Convert to fraction form
    154.78/213.54 = 99.45/x
  3. Step 3: Cross multiply
    154.78x = 213.54 × 99.45
  4. Step 4: Simplify right side
    154.78x = 21,236.55
  5. Step 5: Solve for x
    x = 21,236.55/154.78
  6. Step 6: Final answer
    x = 137.20

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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.