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Finding the Fourth Proportional to 430.98, 644.84 and 261.31

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Solution

The fourth proportional to 430.98, 644.84 and 261.31 is: 390.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.98 : 644.84 = 261.31 : x
  2. Step 2: Convert to fraction form
    430.98/644.84 = 261.31/x
  3. Step 3: Cross multiply
    430.98x = 644.84 × 261.31
  4. Step 4: Simplify right side
    430.98x = 168,503.88
  5. Step 5: Solve for x
    x = 168,503.88/430.98
  6. Step 6: Final answer
    x = 390.98

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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.