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Finding the Fourth Proportional to 788.37, 1,089 and 642.84

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Solution

The fourth proportional to 788.37, 1,089 and 642.84 is: 887.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.37 : 1,089 = 642.84 : x
  2. Step 2: Convert to fraction form
    788.37/1,089 = 642.84/x
  3. Step 3: Cross multiply
    788.37x = 1,089 × 642.84
  4. Step 4: Simplify right side
    788.37x = 700,052.76
  5. Step 5: Solve for x
    x = 700,052.76/788.37
  6. Step 6: Final answer
    x = 887.97

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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.