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Finding the Fourth Proportional to 432.05, 643.74 and 420.44

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Solution

The fourth proportional to 432.05, 643.74 and 420.44 is: 626.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.05 : 643.74 = 420.44 : x
  2. Step 2: Convert to fraction form
    432.05/643.74 = 420.44/x
  3. Step 3: Cross multiply
    432.05x = 643.74 × 420.44
  4. Step 4: Simplify right side
    432.05x = 270,649.25
  5. Step 5: Solve for x
    x = 270,649.25/432.05
  6. Step 6: Final answer
    x = 626.44

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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.