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Finding the Fourth Proportional to 806.75, 1,209.81 and 258.78

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Solution

The fourth proportional to 806.75, 1,209.81 and 258.78 is: 388.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.75 : 1,209.81 = 258.78 : x
  2. Step 2: Convert to fraction form
    806.75/1,209.81 = 258.78/x
  3. Step 3: Cross multiply
    806.75x = 1,209.81 × 258.78
  4. Step 4: Simplify right side
    806.75x = 313,074.63
  5. Step 5: Solve for x
    x = 313,074.63/806.75
  6. Step 6: Final answer
    x = 388.07

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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.