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Finding the Fourth Proportional to 405.22, 558.78 and 311.98

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Solution

The fourth proportional to 405.22, 558.78 and 311.98 is: 430.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.22 : 558.78 = 311.98 : x
  2. Step 2: Convert to fraction form
    405.22/558.78 = 311.98/x
  3. Step 3: Cross multiply
    405.22x = 558.78 × 311.98
  4. Step 4: Simplify right side
    405.22x = 174,328.18
  5. Step 5: Solve for x
    x = 174,328.18/405.22
  6. Step 6: Final answer
    x = 430.21

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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.