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Finding the Fourth Proportional to 211.30, 291.66 and 128.37

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Solution

The fourth proportional to 211.30, 291.66 and 128.37 is: 177.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.30 : 291.66 = 128.37 : x
  2. Step 2: Convert to fraction form
    211.30/291.66 = 128.37/x
  3. Step 3: Cross multiply
    211.30x = 291.66 × 128.37
  4. Step 4: Simplify right side
    211.30x = 37,440.39
  5. Step 5: Solve for x
    x = 37,440.39/211.30
  6. Step 6: Final answer
    x = 177.19

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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.