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Finding the Fourth Proportional to 158.78, 219.04 and 99.79

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Solution

The fourth proportional to 158.78, 219.04 and 99.79 is: 137.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.78 : 219.04 = 99.79 : x
  2. Step 2: Convert to fraction form
    158.78/219.04 = 99.79/x
  3. Step 3: Cross multiply
    158.78x = 219.04 × 99.79
  4. Step 4: Simplify right side
    158.78x = 21,856.41
  5. Step 5: Solve for x
    x = 21,856.41/158.78
  6. Step 6: Final answer
    x = 137.66

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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.