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Finding the Fourth Proportional to 210.97, 291.20 and 128.05

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Solution

The fourth proportional to 210.97, 291.20 and 128.05 is: 176.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.97 : 291.20 = 128.05 : x
  2. Step 2: Convert to fraction form
    210.97/291.20 = 128.05/x
  3. Step 3: Cross multiply
    210.97x = 291.20 × 128.05
  4. Step 4: Simplify right side
    210.97x = 37,286.79
  5. Step 5: Solve for x
    x = 37,286.79/210.97
  6. Step 6: Final answer
    x = 176.74

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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.