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Finding the Fourth Proportional to 420.74, 579.68 and 315.67

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Solution

The fourth proportional to 420.74, 579.68 and 315.67 is: 434.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.74 : 579.68 = 315.67 : x
  2. Step 2: Convert to fraction form
    420.74/579.68 = 315.67/x
  3. Step 3: Cross multiply
    420.74x = 579.68 × 315.67
  4. Step 4: Simplify right side
    420.74x = 182,984.56
  5. Step 5: Solve for x
    x = 182,984.56/420.74
  6. Step 6: Final answer
    x = 434.91

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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.