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Finding the Fourth Proportional to 158.76, 219.09 and 99.78

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Solution

The fourth proportional to 158.76, 219.09 and 99.78 is: 137.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.76 : 219.09 = 99.78 : x
  2. Step 2: Convert to fraction form
    158.76/219.09 = 99.78/x
  3. Step 3: Cross multiply
    158.76x = 219.09 × 99.78
  4. Step 4: Simplify right side
    158.76x = 21,860.80
  5. Step 5: Solve for x
    x = 21,860.80/158.76
  6. Step 6: Final answer
    x = 137.70

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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.