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Finding the Fourth Proportional to 420.21, 579.57 and 289.53

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Solution

The fourth proportional to 420.21, 579.57 and 289.53 is: 399.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.21 : 579.57 = 289.53 : x
  2. Step 2: Convert to fraction form
    420.21/579.57 = 289.53/x
  3. Step 3: Cross multiply
    420.21x = 579.57 × 289.53
  4. Step 4: Simplify right side
    420.21x = 167,802.90
  5. Step 5: Solve for x
    x = 167,802.90/420.21
  6. Step 6: Final answer
    x = 399.33

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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.