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Finding the Fourth Proportional to 490.87, 678.27 and 393.40

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Solution

The fourth proportional to 490.87, 678.27 and 393.40 is: 543.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    490.87 : 678.27 = 393.40 : x
  2. Step 2: Convert to fraction form
    490.87/678.27 = 393.40/x
  3. Step 3: Cross multiply
    490.87x = 678.27 × 393.40
  4. Step 4: Simplify right side
    490.87x = 266,831.42
  5. Step 5: Solve for x
    x = 266,831.42/490.87
  6. Step 6: Final answer
    x = 543.59

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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.