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Finding the Fourth Proportional to 211.58, 316.99 and 138.31

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Solution

The fourth proportional to 211.58, 316.99 and 138.31 is: 207.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.58 : 316.99 = 138.31 : x
  2. Step 2: Convert to fraction form
    211.58/316.99 = 138.31/x
  3. Step 3: Cross multiply
    211.58x = 316.99 × 138.31
  4. Step 4: Simplify right side
    211.58x = 43,842.89
  5. Step 5: Solve for x
    x = 43,842.89/211.58
  6. Step 6: Final answer
    x = 207.22

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.