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Finding the Fourth Proportional to 891.40, 1,338.70 and 648.20

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Solution

The fourth proportional to 891.40, 1,338.70 and 648.20 is: 973.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.40 : 1,338.70 = 648.20 : x
  2. Step 2: Convert to fraction form
    891.40/1,338.70 = 648.20/x
  3. Step 3: Cross multiply
    891.40x = 1,338.70 × 648.20
  4. Step 4: Simplify right side
    891.40x = 867,745.34
  5. Step 5: Solve for x
    x = 867,745.34/891.40
  6. Step 6: Final answer
    x = 973.46

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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.