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Finding the Fourth Proportional to 420.66, 579.87 and 309.95

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Solution

The fourth proportional to 420.66, 579.87 and 309.95 is: 427.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.66 : 579.87 = 309.95 : x
  2. Step 2: Convert to fraction form
    420.66/579.87 = 309.95/x
  3. Step 3: Cross multiply
    420.66x = 579.87 × 309.95
  4. Step 4: Simplify right side
    420.66x = 179,729.98
  5. Step 5: Solve for x
    x = 179,729.98/420.66
  6. Step 6: Final answer
    x = 427.26

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.