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Finding the Fourth Proportional to 209.79, 314.55 and 79.74

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Solution

The fourth proportional to 209.79, 314.55 and 79.74 is: 119.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.79 : 314.55 = 79.74 : x
  2. Step 2: Convert to fraction form
    209.79/314.55 = 79.74/x
  3. Step 3: Cross multiply
    209.79x = 314.55 × 79.74
  4. Step 4: Simplify right side
    209.79x = 25,082.22
  5. Step 5: Solve for x
    x = 25,082.22/209.79
  6. Step 6: Final answer
    x = 119.56

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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.