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Finding the Fourth Proportional to 154.20, 212.58 and 129.60

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Solution

The fourth proportional to 154.20, 212.58 and 129.60 is: 178.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.20 : 212.58 = 129.60 : x
  2. Step 2: Convert to fraction form
    154.20/212.58 = 129.60/x
  3. Step 3: Cross multiply
    154.20x = 212.58 × 129.60
  4. Step 4: Simplify right side
    154.20x = 27,550.37
  5. Step 5: Solve for x
    x = 27,550.37/154.20
  6. Step 6: Final answer
    x = 178.67

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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.