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Finding the Fourth Proportional to 420.18, 629.75 and 145.95

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Solution

The fourth proportional to 420.18, 629.75 and 145.95 is: 218.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.18 : 629.75 = 145.95 : x
  2. Step 2: Convert to fraction form
    420.18/629.75 = 145.95/x
  3. Step 3: Cross multiply
    420.18x = 629.75 × 145.95
  4. Step 4: Simplify right side
    420.18x = 91,913.56
  5. Step 5: Solve for x
    x = 91,913.56/420.18
  6. Step 6: Final answer
    x = 218.75

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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.