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Finding the Fourth Proportional to 978.80, 1,349.64 and 768.29

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Solution

The fourth proportional to 978.80, 1,349.64 and 768.29 is: 1,059.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.80 : 1,349.64 = 768.29 : x
  2. Step 2: Convert to fraction form
    978.80/1,349.64 = 768.29/x
  3. Step 3: Cross multiply
    978.80x = 1,349.64 × 768.29
  4. Step 4: Simplify right side
    978.80x = 1,036,908.17
  5. Step 5: Solve for x
    x = 1,036,908.17/978.80
  6. Step 6: Final answer
    x = 1,059.37

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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.