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Finding the Fourth Proportional to 788.84, 1,087.80 and 640.88

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Solution

The fourth proportional to 788.84, 1,087.80 and 640.88 is: 883.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.84 : 1,087.80 = 640.88 : x
  2. Step 2: Convert to fraction form
    788.84/1,087.80 = 640.88/x
  3. Step 3: Cross multiply
    788.84x = 1,087.80 × 640.88
  4. Step 4: Simplify right side
    788.84x = 697,149.26
  5. Step 5: Solve for x
    x = 697,149.26/788.84
  6. Step 6: Final answer
    x = 883.77

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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.