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Finding the Fourth Proportional to 211.09, 316.79 and 139.11

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Solution

The fourth proportional to 211.09, 316.79 and 139.11 is: 208.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.09 : 316.79 = 139.11 : x
  2. Step 2: Convert to fraction form
    211.09/316.79 = 139.11/x
  3. Step 3: Cross multiply
    211.09x = 316.79 × 139.11
  4. Step 4: Simplify right side
    211.09x = 44,068.66
  5. Step 5: Solve for x
    x = 44,068.66/211.09
  6. Step 6: Final answer
    x = 208.77

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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.