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Finding the Fourth Proportional to 928.80, 1,387.90 and 667.58

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Solution

The fourth proportional to 928.80, 1,387.90 and 667.58 is: 997.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.80 : 1,387.90 = 667.58 : x
  2. Step 2: Convert to fraction form
    928.80/1,387.90 = 667.58/x
  3. Step 3: Cross multiply
    928.80x = 1,387.90 × 667.58
  4. Step 4: Simplify right side
    928.80x = 926,528.18
  5. Step 5: Solve for x
    x = 926,528.18/928.80
  6. Step 6: Final answer
    x = 997.55

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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.