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Finding the Fourth Proportional to 399.81, 599.64 and 139.80

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Solution

The fourth proportional to 399.81, 599.64 and 139.80 is: 209.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.81 : 599.64 = 139.80 : x
  2. Step 2: Convert to fraction form
    399.81/599.64 = 139.80/x
  3. Step 3: Cross multiply
    399.81x = 599.64 × 139.80
  4. Step 4: Simplify right side
    399.81x = 83,830.30
  5. Step 5: Solve for x
    x = 83,830.30/399.81
  6. Step 6: Final answer
    x = 209.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.