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Finding the Fourth Proportional to 891.20, 1,336.80 and 275.20

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Solution

The fourth proportional to 891.20, 1,336.80 and 275.20 is: 412.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.20 : 1,336.80 = 275.20 : x
  2. Step 2: Convert to fraction form
    891.20/1,336.80 = 275.20/x
  3. Step 3: Cross multiply
    891.20x = 1,336.80 × 275.20
  4. Step 4: Simplify right side
    891.20x = 367,885.05
  5. Step 5: Solve for x
    x = 367,885.05/891.20
  6. Step 6: Final answer
    x = 412.80

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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.