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Finding the Fourth Proportional to 420.57, 580.70 and 315.84

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Solution

The fourth proportional to 420.57, 580.70 and 315.84 is: 436.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.57 : 580.70 = 315.84 : x
  2. Step 2: Convert to fraction form
    420.57/580.70 = 315.84/x
  3. Step 3: Cross multiply
    420.57x = 580.70 × 315.84
  4. Step 4: Simplify right side
    420.57x = 183,406.71
  5. Step 5: Solve for x
    x = 183,406.71/420.57
  6. Step 6: Final answer
    x = 436.09

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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.