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Finding the Fourth Proportional to 405.45, 558.74 and 312.20

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Solution

The fourth proportional to 405.45, 558.74 and 312.20 is: 430.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.45 : 558.74 = 312.20 : x
  2. Step 2: Convert to fraction form
    405.45/558.74 = 312.20/x
  3. Step 3: Cross multiply
    405.45x = 558.74 × 312.20
  4. Step 4: Simplify right side
    405.45x = 174,434.27
  5. Step 5: Solve for x
    x = 174,434.27/405.45
  6. Step 6: Final answer
    x = 430.22

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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.