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Finding the Fourth Proportional to 455.31, 679.67 and 421.50

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Solution

The fourth proportional to 455.31, 679.67 and 421.50 is: 629.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.31 : 679.67 = 421.50 : x
  2. Step 2: Convert to fraction form
    455.31/679.67 = 421.50/x
  3. Step 3: Cross multiply
    455.31x = 679.67 × 421.50
  4. Step 4: Simplify right side
    455.31x = 286,480.91
  5. Step 5: Solve for x
    x = 286,480.91/455.31
  6. Step 6: Final answer
    x = 629.20

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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.