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Finding the Fourth Proportional to 420.30, 626.87 and 408.75

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Solution

The fourth proportional to 420.30, 626.87 and 408.75 is: 609.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.30 : 626.87 = 408.75 : x
  2. Step 2: Convert to fraction form
    420.30/626.87 = 408.75/x
  3. Step 3: Cross multiply
    420.30x = 626.87 × 408.75
  4. Step 4: Simplify right side
    420.30x = 256,231.07
  5. Step 5: Solve for x
    x = 256,231.07/420.30
  6. Step 6: Final answer
    x = 609.64

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.