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Finding the Fourth Proportional to 979.37, 1,351.59 and 647.21

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Solution

The fourth proportional to 979.37, 1,351.59 and 647.21 is: 893.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.37 : 1,351.59 = 647.21 : x
  2. Step 2: Convert to fraction form
    979.37/1,351.59 = 647.21/x
  3. Step 3: Cross multiply
    979.37x = 1,351.59 × 647.21
  4. Step 4: Simplify right side
    979.37x = 874,765.94
  5. Step 5: Solve for x
    x = 874,765.94/979.37
  6. Step 6: Final answer
    x = 893.20

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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.