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Finding the Fourth Proportional to 430.80, 645.63 and 426.21

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Solution

The fourth proportional to 430.80, 645.63 and 426.21 is: 638.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.80 : 645.63 = 426.21 : x
  2. Step 2: Convert to fraction form
    430.80/645.63 = 426.21/x
  3. Step 3: Cross multiply
    430.80x = 645.63 × 426.21
  4. Step 4: Simplify right side
    430.80x = 275,173.96
  5. Step 5: Solve for x
    x = 275,173.96/430.80
  6. Step 6: Final answer
    x = 638.75

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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.