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Finding the Fourth Proportional to 978.45, 1,350.38 and 647.56

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Solution

The fourth proportional to 978.45, 1,350.38 and 647.56 is: 893.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.45 : 1,350.38 = 647.56 : x
  2. Step 2: Convert to fraction form
    978.45/1,350.38 = 647.56/x
  3. Step 3: Cross multiply
    978.45x = 1,350.38 × 647.56
  4. Step 4: Simplify right side
    978.45x = 874,452.07
  5. Step 5: Solve for x
    x = 874,452.07/978.45
  6. Step 6: Final answer
    x = 893.71

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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.