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Finding the Fourth Proportional to 420.65, 630.78 and 146.71

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Solution

The fourth proportional to 420.65, 630.78 and 146.71 is: 219.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.65 : 630.78 = 146.71 : x
  2. Step 2: Convert to fraction form
    420.65/630.78 = 146.71/x
  3. Step 3: Cross multiply
    420.65x = 630.78 × 146.71
  4. Step 4: Simplify right side
    420.65x = 92,539.79
  5. Step 5: Solve for x
    x = 92,539.79/420.65
  6. Step 6: Final answer
    x = 219.99

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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.