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Finding the Fourth Proportional to 680.90, 939.70 and 386.22

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Solution

The fourth proportional to 680.90, 939.70 and 386.22 is: 533.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.90 : 939.70 = 386.22 : x
  2. Step 2: Convert to fraction form
    680.90/939.70 = 386.22/x
  3. Step 3: Cross multiply
    680.90x = 939.70 × 386.22
  4. Step 4: Simplify right side
    680.90x = 362,930.93
  5. Step 5: Solve for x
    x = 362,930.93/680.90
  6. Step 6: Final answer
    x = 533.02

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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.