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Finding the Fourth Proportional to 980.31, 1,352.21 and 665.63

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Solution

The fourth proportional to 980.31, 1,352.21 and 665.63 is: 918.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.31 : 1,352.21 = 665.63 : x
  2. Step 2: Convert to fraction form
    980.31/1,352.21 = 665.63/x
  3. Step 3: Cross multiply
    980.31x = 1,352.21 × 665.63
  4. Step 4: Simplify right side
    980.31x = 900,071.54
  5. Step 5: Solve for x
    x = 900,071.54/980.31
  6. Step 6: Final answer
    x = 918.15

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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.