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Finding the Fourth Proportional to 680.99, 939.80 and 386.15

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Solution

The fourth proportional to 680.99, 939.80 and 386.15 is: 532.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.99 : 939.80 = 386.15 : x
  2. Step 2: Convert to fraction form
    680.99/939.80 = 386.15/x
  3. Step 3: Cross multiply
    680.99x = 939.80 × 386.15
  4. Step 4: Simplify right side
    680.99x = 362,900.04
  5. Step 5: Solve for x
    x = 362,900.04/680.99
  6. Step 6: Final answer
    x = 532.90

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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.