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Finding the Fourth Proportional to 806.78, 1,209.87 and 258.86

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Solution

The fourth proportional to 806.78, 1,209.87 and 258.86 is: 388.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.78 : 1,209.87 = 258.86 : x
  2. Step 2: Convert to fraction form
    806.78/1,209.87 = 258.86/x
  3. Step 3: Cross multiply
    806.78x = 1,209.87 × 258.86
  4. Step 4: Simplify right side
    806.78x = 313,186.95
  5. Step 5: Solve for x
    x = 313,186.95/806.78
  6. Step 6: Final answer
    x = 388.19

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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.