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Finding the Fourth Proportional to 426.45, 640.90 and 253.21

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Solution

The fourth proportional to 426.45, 640.90 and 253.21 is: 380.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.45 : 640.90 = 253.21 : x
  2. Step 2: Convert to fraction form
    426.45/640.90 = 253.21/x
  3. Step 3: Cross multiply
    426.45x = 640.90 × 253.21
  4. Step 4: Simplify right side
    426.45x = 162,282.29
  5. Step 5: Solve for x
    x = 162,282.29/426.45
  6. Step 6: Final answer
    x = 380.54

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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.