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Finding the Fourth Proportional to 891.24, 1,336.64 and 428.80

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Solution

The fourth proportional to 891.24, 1,336.64 and 428.80 is: 643.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.24 : 1,336.64 = 428.80 : x
  2. Step 2: Convert to fraction form
    891.24/1,336.64 = 428.80/x
  3. Step 3: Cross multiply
    891.24x = 1,336.64 × 428.80
  4. Step 4: Simplify right side
    891.24x = 573,151.23
  5. Step 5: Solve for x
    x = 573,151.23/891.24
  6. Step 6: Final answer
    x = 643.09

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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.