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Finding the Fourth Proportional to 921.78, 1,388.04 and 680.00

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Solution

The fourth proportional to 921.78, 1,388.04 and 680.00 is: 1,023.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.78 : 1,388.04 = 680.00 : x
  2. Step 2: Convert to fraction form
    921.78/1,388.04 = 680.00/x
  3. Step 3: Cross multiply
    921.78x = 1,388.04 × 680.00
  4. Step 4: Simplify right side
    921.78x = 943,857.71
  5. Step 5: Solve for x
    x = 943,857.71/921.78
  6. Step 6: Final answer
    x = 1,023.95

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.