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Finding the Fourth Proportional to 259.80, 391.49 and 215.15

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Solution

The fourth proportional to 259.80, 391.49 and 215.15 is: 324.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.80 : 391.49 = 215.15 : x
  2. Step 2: Convert to fraction form
    259.80/391.49 = 215.15/x
  3. Step 3: Cross multiply
    259.80x = 391.49 × 215.15
  4. Step 4: Simplify right side
    259.80x = 84,226.04
  5. Step 5: Solve for x
    x = 84,226.04/259.80
  6. Step 6: Final answer
    x = 324.20

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.