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Finding the Fourth Proportional to 211.90, 317.26 and 138.56

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Solution

The fourth proportional to 211.90, 317.26 and 138.56 is: 207.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.90 : 317.26 = 138.56 : x
  2. Step 2: Convert to fraction form
    211.90/317.26 = 138.56/x
  3. Step 3: Cross multiply
    211.90x = 317.26 × 138.56
  4. Step 4: Simplify right side
    211.90x = 43,957.27
  5. Step 5: Solve for x
    x = 43,957.27/211.90
  6. Step 6: Final answer
    x = 207.45

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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.