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Finding the Fourth Proportional to 211.56, 317.40 and 139.32

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Solution

The fourth proportional to 211.56, 317.40 and 139.32 is: 209.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.56 : 317.40 = 139.32 : x
  2. Step 2: Convert to fraction form
    211.56/317.40 = 139.32/x
  3. Step 3: Cross multiply
    211.56x = 317.40 × 139.32
  4. Step 4: Simplify right side
    211.56x = 44,220.17
  5. Step 5: Solve for x
    x = 44,220.17/211.56
  6. Step 6: Final answer
    x = 209.02

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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.