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Finding the Fourth Proportional to 891.68, 1,230.34 and 643.37

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Solution

The fourth proportional to 891.68, 1,230.34 and 643.37 is: 887.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.68 : 1,230.34 = 643.37 : x
  2. Step 2: Convert to fraction form
    891.68/1,230.34 = 643.37/x
  3. Step 3: Cross multiply
    891.68x = 1,230.34 × 643.37
  4. Step 4: Simplify right side
    891.68x = 791,560.63
  5. Step 5: Solve for x
    x = 791,560.63/891.68
  6. Step 6: Final answer
    x = 887.72

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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.