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Finding the Fourth Proportional to 158.78, 238.36 and 86.70

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Solution

The fourth proportional to 158.78, 238.36 and 86.70 is: 130.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.78 : 238.36 = 86.70 : x
  2. Step 2: Convert to fraction form
    158.78/238.36 = 86.70/x
  3. Step 3: Cross multiply
    158.78x = 238.36 × 86.70
  4. Step 4: Simplify right side
    158.78x = 20,665.81
  5. Step 5: Solve for x
    x = 20,665.81/158.78
  6. Step 6: Final answer
    x = 130.15

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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.