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Finding the Fourth Proportional to 209.67, 314.51 and 128.99

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Solution

The fourth proportional to 209.67, 314.51 and 128.99 is: 193.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.67 : 314.51 = 128.99 : x
  2. Step 2: Convert to fraction form
    209.67/314.51 = 128.99/x
  3. Step 3: Cross multiply
    209.67x = 314.51 × 128.99
  4. Step 4: Simplify right side
    209.67x = 40,566.43
  5. Step 5: Solve for x
    x = 40,566.43/209.67
  6. Step 6: Final answer
    x = 193.48

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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.