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Finding the Fourth Proportional to 424.32, 636.40 and 218.80

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Solution

The fourth proportional to 424.32, 636.40 and 218.80 is: 328.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    424.32 : 636.40 = 218.80 : x
  2. Step 2: Convert to fraction form
    424.32/636.40 = 218.80/x
  3. Step 3: Cross multiply
    424.32x = 636.40 × 218.80
  4. Step 4: Simplify right side
    424.32x = 139,244.32
  5. Step 5: Solve for x
    x = 139,244.32/424.32
  6. Step 6: Final answer
    x = 328.16

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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.