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Finding the Fourth Proportional to 211.16, 291.18 and 128.23

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Solution

The fourth proportional to 211.16, 291.18 and 128.23 is: 176.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.16 : 291.18 = 128.23 : x
  2. Step 2: Convert to fraction form
    211.16/291.18 = 128.23/x
  3. Step 3: Cross multiply
    211.16x = 291.18 × 128.23
  4. Step 4: Simplify right side
    211.16x = 37,338.26
  5. Step 5: Solve for x
    x = 37,338.26/211.16
  6. Step 6: Final answer
    x = 176.83

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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.