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Finding the Fourth Proportional to 680.40, 939.60 and 448.20

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Solution

The fourth proportional to 680.40, 939.60 and 448.20 is: 618.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.40 : 939.60 = 448.20 : x
  2. Step 2: Convert to fraction form
    680.40/939.60 = 448.20/x
  3. Step 3: Cross multiply
    680.40x = 939.60 × 448.20
  4. Step 4: Simplify right side
    680.40x = 421,128.72
  5. Step 5: Solve for x
    x = 421,128.72/680.40
  6. Step 6: Final answer
    x = 618.94

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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.