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Finding the Fourth Proportional to 405.42, 561.09 and 395.72

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Solution

The fourth proportional to 405.42, 561.09 and 395.72 is: 547.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.42 : 561.09 = 395.72 : x
  2. Step 2: Convert to fraction form
    405.42/561.09 = 395.72/x
  3. Step 3: Cross multiply
    405.42x = 561.09 × 395.72
  4. Step 4: Simplify right side
    405.42x = 222,034.53
  5. Step 5: Solve for x
    x = 222,034.53/405.42
  6. Step 6: Final answer
    x = 547.67

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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.