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Finding the Fourth Proportional to 891.12, 1,229.10 and 688.50

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Solution

The fourth proportional to 891.12, 1,229.10 and 688.50 is: 949.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.12 : 1,229.10 = 688.50 : x
  2. Step 2: Convert to fraction form
    891.12/1,229.10 = 688.50/x
  3. Step 3: Cross multiply
    891.12x = 1,229.10 × 688.50
  4. Step 4: Simplify right side
    891.12x = 846,235.35
  5. Step 5: Solve for x
    x = 846,235.35/891.12
  6. Step 6: Final answer
    x = 949.63

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.