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Finding the Fourth Proportional to 211.34, 291.62 and 128.40

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Solution

The fourth proportional to 211.34, 291.62 and 128.40 is: 177.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.34 : 291.62 = 128.40 : x
  2. Step 2: Convert to fraction form
    211.34/291.62 = 128.40/x
  3. Step 3: Cross multiply
    211.34x = 291.62 × 128.40
  4. Step 4: Simplify right side
    211.34x = 37,443.37
  5. Step 5: Solve for x
    x = 37,443.37/211.34
  6. Step 6: Final answer
    x = 177.18

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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.