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Finding the Fourth Proportional to 154.64, 212.50 and 128.72

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Solution

The fourth proportional to 154.64, 212.50 and 128.72 is: 176.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.64 : 212.50 = 128.72 : x
  2. Step 2: Convert to fraction form
    154.64/212.50 = 128.72/x
  3. Step 3: Cross multiply
    154.64x = 212.50 × 128.72
  4. Step 4: Simplify right side
    154.64x = 27,353
  5. Step 5: Solve for x
    x = 27,353/154.64
  6. Step 6: Final answer
    x = 176.88

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.