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Finding the Fourth Proportional to 928.41, 1,392.08 and 639.51

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Solution

The fourth proportional to 928.41, 1,392.08 and 639.51 is: 958.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.41 : 1,392.08 = 639.51 : x
  2. Step 2: Convert to fraction form
    928.41/1,392.08 = 639.51/x
  3. Step 3: Cross multiply
    928.41x = 1,392.08 × 639.51
  4. Step 4: Simplify right side
    928.41x = 890,245.88
  5. Step 5: Solve for x
    x = 890,245.88/928.41
  6. Step 6: Final answer
    x = 958.89

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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.