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Finding the Fourth Proportional to 891.68, 1,336.52 and 428.80

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Solution

The fourth proportional to 891.68, 1,336.52 and 428.80 is: 642.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.68 : 1,336.52 = 428.80 : x
  2. Step 2: Convert to fraction form
    891.68/1,336.52 = 428.80/x
  3. Step 3: Cross multiply
    891.68x = 1,336.52 × 428.80
  4. Step 4: Simplify right side
    891.68x = 573,099.78
  5. Step 5: Solve for x
    x = 573,099.78/891.68
  6. Step 6: Final answer
    x = 642.72

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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.