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Finding the Fourth Proportional to 212.53, 318.78 and 66.28

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Solution

The fourth proportional to 212.53, 318.78 and 66.28 is: 99.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.53 : 318.78 = 66.28 : x
  2. Step 2: Convert to fraction form
    212.53/318.78 = 66.28/x
  3. Step 3: Cross multiply
    212.53x = 318.78 × 66.28
  4. Step 4: Simplify right side
    212.53x = 21,128.74
  5. Step 5: Solve for x
    x = 21,128.74/212.53
  6. Step 6: Final answer
    x = 99.42

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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.