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Finding the Fourth Proportional to 211.87, 317.66 and 138.77

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Solution

The fourth proportional to 211.87, 317.66 and 138.77 is: 208.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.87 : 317.66 = 138.77 : x
  2. Step 2: Convert to fraction form
    211.87/317.66 = 138.77/x
  3. Step 3: Cross multiply
    211.87x = 317.66 × 138.77
  4. Step 4: Simplify right side
    211.87x = 44,080.59
  5. Step 5: Solve for x
    x = 44,080.59/211.87
  6. Step 6: Final answer
    x = 208.05

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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.