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Finding the Fourth Proportional to 420.21, 629.40 and 273.60

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Solution

The fourth proportional to 420.21, 629.40 and 273.60 is: 409.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.21 : 629.40 = 273.60 : x
  2. Step 2: Convert to fraction form
    420.21/629.40 = 273.60/x
  3. Step 3: Cross multiply
    420.21x = 629.40 × 273.60
  4. Step 4: Simplify right side
    420.21x = 172,203.84
  5. Step 5: Solve for x
    x = 172,203.84/420.21
  6. Step 6: Final answer
    x = 409.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.