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Finding the Fourth Proportional to 211.18, 291.40 and 128.14

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Solution

The fourth proportional to 211.18, 291.40 and 128.14 is: 176.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.18 : 291.40 = 128.14 : x
  2. Step 2: Convert to fraction form
    211.18/291.40 = 128.14/x
  3. Step 3: Cross multiply
    211.18x = 291.40 × 128.14
  4. Step 4: Simplify right side
    211.18x = 37,341.40
  5. Step 5: Solve for x
    x = 37,341.40/211.18
  6. Step 6: Final answer
    x = 176.82

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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.