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Finding the Fourth Proportional to 680.79, 939.70 and 386.25

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Solution

The fourth proportional to 680.79, 939.70 and 386.25 is: 533.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.79 : 939.70 = 386.25 : x
  2. Step 2: Convert to fraction form
    680.79/939.70 = 386.25/x
  3. Step 3: Cross multiply
    680.79x = 939.70 × 386.25
  4. Step 4: Simplify right side
    680.79x = 362,961.37
  5. Step 5: Solve for x
    x = 362,961.37/680.79
  6. Step 6: Final answer
    x = 533.15

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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.