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Finding the Fourth Proportional to 978.79, 1,351.47 and 769.99

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Solution

The fourth proportional to 978.79, 1,351.47 and 769.99 is: 1,063.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.79 : 1,351.47 = 769.99 : x
  2. Step 2: Convert to fraction form
    978.79/1,351.47 = 769.99/x
  3. Step 3: Cross multiply
    978.79x = 1,351.47 × 769.99
  4. Step 4: Simplify right side
    978.79x = 1,040,618.39
  5. Step 5: Solve for x
    x = 1,040,618.39/978.79
  6. Step 6: Final answer
    x = 1,063.17

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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.