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Finding the Fourth Proportional to 209.80, 312.51 and 208.81

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Solution

The fourth proportional to 209.80, 312.51 and 208.81 is: 311.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.80 : 312.51 = 208.81 : x
  2. Step 2: Convert to fraction form
    209.80/312.51 = 208.81/x
  3. Step 3: Cross multiply
    209.80x = 312.51 × 208.81
  4. Step 4: Simplify right side
    209.80x = 65,255.21
  5. Step 5: Solve for x
    x = 65,255.21/209.80
  6. Step 6: Final answer
    x = 311.04

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.