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Finding the Fourth Proportional to 405.21, 558.40 and 288.57

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Solution

The fourth proportional to 405.21, 558.40 and 288.57 is: 397.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.21 : 558.40 = 288.57 : x
  2. Step 2: Convert to fraction form
    405.21/558.40 = 288.57/x
  3. Step 3: Cross multiply
    405.21x = 558.40 × 288.57
  4. Step 4: Simplify right side
    405.21x = 161,136.05
  5. Step 5: Solve for x
    x = 161,136.05/405.21
  6. Step 6: Final answer
    x = 397.66

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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.