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Finding the Fourth Proportional to 891.19, 1,230.49 and 643.06

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Solution

The fourth proportional to 891.19, 1,230.49 and 643.06 is: 887.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.19 : 1,230.49 = 643.06 : x
  2. Step 2: Convert to fraction form
    891.19/1,230.49 = 643.06/x
  3. Step 3: Cross multiply
    891.19x = 1,230.49 × 643.06
  4. Step 4: Simplify right side
    891.19x = 791,278.90
  5. Step 5: Solve for x
    x = 791,278.90/891.19
  6. Step 6: Final answer
    x = 887.89

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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.