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Finding the Fourth Proportional to 455.54, 680.00 and 421.70

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Solution

The fourth proportional to 455.54, 680.00 and 421.70 is: 629.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.54 : 680.00 = 421.70 : x
  2. Step 2: Convert to fraction form
    455.54/680.00 = 421.70/x
  3. Step 3: Cross multiply
    455.54x = 680.00 × 421.70
  4. Step 4: Simplify right side
    455.54x = 286,750.49
  5. Step 5: Solve for x
    x = 286,750.49/455.54
  6. Step 6: Final answer
    x = 629.48

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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.