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Finding the Fourth Proportional to 420.05, 580.17 and 315.60

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Solution

The fourth proportional to 420.05, 580.17 and 315.60 is: 435.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.05 : 580.17 = 315.60 : x
  2. Step 2: Convert to fraction form
    420.05/580.17 = 315.60/x
  3. Step 3: Cross multiply
    420.05x = 580.17 × 315.60
  4. Step 4: Simplify right side
    420.05x = 183,101.65
  5. Step 5: Solve for x
    x = 183,101.65/420.05
  6. Step 6: Final answer
    x = 435.91

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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.