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Finding the Fourth Proportional to 890.88, 1,229.94 and 642.84

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Solution

The fourth proportional to 890.88, 1,229.94 and 642.84 is: 887.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.88 : 1,229.94 = 642.84 : x
  2. Step 2: Convert to fraction form
    890.88/1,229.94 = 642.84/x
  3. Step 3: Cross multiply
    890.88x = 1,229.94 × 642.84
  4. Step 4: Simplify right side
    890.88x = 790,654.63
  5. Step 5: Solve for x
    x = 790,654.63/890.88
  6. Step 6: Final answer
    x = 887.50

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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.