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Finding the Fourth Proportional to 420.67, 579.99 and 289.45

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Solution

The fourth proportional to 420.67, 579.99 and 289.45 is: 399.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.67 : 579.99 = 289.45 : x
  2. Step 2: Convert to fraction form
    420.67/579.99 = 289.45/x
  3. Step 3: Cross multiply
    420.67x = 579.99 × 289.45
  4. Step 4: Simplify right side
    420.67x = 167,878.11
  5. Step 5: Solve for x
    x = 167,878.11/420.67
  6. Step 6: Final answer
    x = 399.07

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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.