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Finding the Fourth Proportional to 426.78, 640.71 and 407.16

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Solution

The fourth proportional to 426.78, 640.71 and 407.16 is: 611.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.78 : 640.71 = 407.16 : x
  2. Step 2: Convert to fraction form
    426.78/640.71 = 407.16/x
  3. Step 3: Cross multiply
    426.78x = 640.71 × 407.16
  4. Step 4: Simplify right side
    426.78x = 260,871.48
  5. Step 5: Solve for x
    x = 260,871.48/426.78
  6. Step 6: Final answer
    x = 611.26

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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.