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Finding the Fourth Proportional to 979.72, 1,351.06 and 840.32

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Solution

The fourth proportional to 979.72, 1,351.06 and 840.32 is: 1,158.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.72 : 1,351.06 = 840.32 : x
  2. Step 2: Convert to fraction form
    979.72/1,351.06 = 840.32/x
  3. Step 3: Cross multiply
    979.72x = 1,351.06 × 840.32
  4. Step 4: Simplify right side
    979.72x = 1,135,322.74
  5. Step 5: Solve for x
    x = 1,135,322.74/979.72
  6. Step 6: Final answer
    x = 1,158.82

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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.