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Finding the Fourth Proportional to 420.51, 630.69 and 131.88

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Solution

The fourth proportional to 420.51, 630.69 and 131.88 is: 197.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.51 : 630.69 = 131.88 : x
  2. Step 2: Convert to fraction form
    420.51/630.69 = 131.88/x
  3. Step 3: Cross multiply
    420.51x = 630.69 × 131.88
  4. Step 4: Simplify right side
    420.51x = 83,172.24
  5. Step 5: Solve for x
    x = 83,172.24/420.51
  6. Step 6: Final answer
    x = 197.79

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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.