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Finding the Fourth Proportional to 420.21, 630.18 and 131.67

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Solution

The fourth proportional to 420.21, 630.18 and 131.67 is: 197.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.21 : 630.18 = 131.67 : x
  2. Step 2: Convert to fraction form
    420.21/630.18 = 131.67/x
  3. Step 3: Cross multiply
    420.21x = 630.18 × 131.67
  4. Step 4: Simplify right side
    420.21x = 82,975.80
  5. Step 5: Solve for x
    x = 82,975.80/420.21
  6. Step 6: Final answer
    x = 197.46

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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.