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Finding the Fourth Proportional to 209.85, 314.66 and 79.84

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Solution

The fourth proportional to 209.85, 314.66 and 79.84 is: 119.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.85 : 314.66 = 79.84 : x
  2. Step 2: Convert to fraction form
    209.85/314.66 = 79.84/x
  3. Step 3: Cross multiply
    209.85x = 314.66 × 79.84
  4. Step 4: Simplify right side
    209.85x = 25,122.45
  5. Step 5: Solve for x
    x = 25,122.45/209.85
  6. Step 6: Final answer
    x = 119.72

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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.