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Finding the Fourth Proportional to 431.80, 644.38 and 385.67

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Solution

The fourth proportional to 431.80, 644.38 and 385.67 is: 575.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.80 : 644.38 = 385.67 : x
  2. Step 2: Convert to fraction form
    431.80/644.38 = 385.67/x
  3. Step 3: Cross multiply
    431.80x = 644.38 × 385.67
  4. Step 4: Simplify right side
    431.80x = 248,513.85
  5. Step 5: Solve for x
    x = 248,513.85/431.80
  6. Step 6: Final answer
    x = 575.53

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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.