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Finding the Fourth Proportional to 518.20, 715.85 and 388.81

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Solution

The fourth proportional to 518.20, 715.85 and 388.81 is: 537.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.20 : 715.85 = 388.81 : x
  2. Step 2: Convert to fraction form
    518.20/715.85 = 388.81/x
  3. Step 3: Cross multiply
    518.20x = 715.85 × 388.81
  4. Step 4: Simplify right side
    518.20x = 278,329.64
  5. Step 5: Solve for x
    x = 278,329.64/518.20
  6. Step 6: Final answer
    x = 537.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.