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Finding the Fourth Proportional to 788.28, 1,187.12 and 686.79

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Solution

The fourth proportional to 788.28, 1,187.12 and 686.79 is: 1,034.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.28 : 1,187.12 = 686.79 : x
  2. Step 2: Convert to fraction form
    788.28/1,187.12 = 686.79/x
  3. Step 3: Cross multiply
    788.28x = 1,187.12 × 686.79
  4. Step 4: Simplify right side
    788.28x = 815,298.71
  5. Step 5: Solve for x
    x = 815,298.71/788.28
  6. Step 6: Final answer
    x = 1,034.28

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.