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Finding the Fourth Proportional to 891.26, 1,336.39 and 428.42

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Solution

The fourth proportional to 891.26, 1,336.39 and 428.42 is: 642.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.26 : 1,336.39 = 428.42 : x
  2. Step 2: Convert to fraction form
    891.26/1,336.39 = 428.42/x
  3. Step 3: Cross multiply
    891.26x = 1,336.39 × 428.42
  4. Step 4: Simplify right side
    891.26x = 572,536.20
  5. Step 5: Solve for x
    x = 572,536.20/891.26
  6. Step 6: Final answer
    x = 642.39

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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.