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Finding the Fourth Proportional to 680.48, 939.17 and 638.79

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Solution

The fourth proportional to 680.48, 939.17 and 638.79 is: 881.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.48 : 939.17 = 638.79 : x
  2. Step 2: Convert to fraction form
    680.48/939.17 = 638.79/x
  3. Step 3: Cross multiply
    680.48x = 939.17 × 638.79
  4. Step 4: Simplify right side
    680.48x = 599,929.21
  5. Step 5: Solve for x
    x = 599,929.21/680.48
  6. Step 6: Final answer
    x = 881.63

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1.5x scale

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.