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Finding the Fourth Proportional to 445.68, 665.64 and 420.84

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Solution

The fourth proportional to 445.68, 665.64 and 420.84 is: 628.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    445.68 : 665.64 = 420.84 : x
  2. Step 2: Convert to fraction form
    445.68/665.64 = 420.84/x
  3. Step 3: Cross multiply
    445.68x = 665.64 × 420.84
  4. Step 4: Simplify right side
    445.68x = 280,127.94
  5. Step 5: Solve for x
    x = 280,127.94/445.68
  6. Step 6: Final answer
    x = 628.54

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.