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Finding the Fourth Proportional to 648.45, 894.69 and 399.78

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Solution

The fourth proportional to 648.45, 894.69 and 399.78 is: 551.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    648.45 : 894.69 = 399.78 : x
  2. Step 2: Convert to fraction form
    648.45/894.69 = 399.78/x
  3. Step 3: Cross multiply
    648.45x = 894.69 × 399.78
  4. Step 4: Simplify right side
    648.45x = 357,679.17
  5. Step 5: Solve for x
    x = 357,679.17/648.45
  6. Step 6: Final answer
    x = 551.59

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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.