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Finding the Fourth Proportional to 420.10, 580.02 and 309.70

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Solution

The fourth proportional to 420.10, 580.02 and 309.70 is: 427.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.10 : 580.02 = 309.70 : x
  2. Step 2: Convert to fraction form
    420.10/580.02 = 309.70/x
  3. Step 3: Cross multiply
    420.10x = 580.02 × 309.70
  4. Step 4: Simplify right side
    420.10x = 179,632.19
  5. Step 5: Solve for x
    x = 179,632.19/420.10
  6. Step 6: Final answer
    x = 427.59

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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.