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Finding the Fourth Proportional to 891.13, 1,228.10 and 642.02

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Solution

The fourth proportional to 891.13, 1,228.10 and 642.02 is: 884.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.13 : 1,228.10 = 642.02 : x
  2. Step 2: Convert to fraction form
    891.13/1,228.10 = 642.02/x
  3. Step 3: Cross multiply
    891.13x = 1,228.10 × 642.02
  4. Step 4: Simplify right side
    891.13x = 788,464.76
  5. Step 5: Solve for x
    x = 788,464.76/891.13
  6. Step 6: Final answer
    x = 884.79

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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.