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Finding the Fourth Proportional to 390.87, 537.78 and 388.35

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Solution

The fourth proportional to 390.87, 537.78 and 388.35 is: 534.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.87 : 537.78 = 388.35 : x
  2. Step 2: Convert to fraction form
    390.87/537.78 = 388.35/x
  3. Step 3: Cross multiply
    390.87x = 537.78 × 388.35
  4. Step 4: Simplify right side
    390.87x = 208,846.86
  5. Step 5: Solve for x
    x = 208,846.86/390.87
  6. Step 6: Final answer
    x = 534.31

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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.