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Finding the Fourth Proportional to 158.40, 218.72 and 136.72

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Solution

The fourth proportional to 158.40, 218.72 and 136.72 is: 188.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    158.40 : 218.72 = 136.72 : x
  2. Step 2: Convert to fraction form
    158.40/218.72 = 136.72/x
  3. Step 3: Cross multiply
    158.40x = 218.72 × 136.72
  4. Step 4: Simplify right side
    158.40x = 29,903.40
  5. Step 5: Solve for x
    x = 29,903.40/158.40
  6. Step 6: Final answer
    x = 188.78

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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.