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Finding the Fourth Proportional to 455.78, 680.37 and 421.49

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Solution

The fourth proportional to 455.78, 680.37 and 421.49 is: 629.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.78 : 680.37 = 421.49 : x
  2. Step 2: Convert to fraction form
    455.78/680.37 = 421.49/x
  3. Step 3: Cross multiply
    455.78x = 680.37 × 421.49
  4. Step 4: Simplify right side
    455.78x = 286,767.04
  5. Step 5: Solve for x
    x = 286,767.04/455.78
  6. Step 6: Final answer
    x = 629.18

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.