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Finding the Fourth Proportional to 212.40, 316.90 and 189.30

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Solution

The fourth proportional to 212.40, 316.90 and 189.30 is: 282.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.40 : 316.90 = 189.30 : x
  2. Step 2: Convert to fraction form
    212.40/316.90 = 189.30/x
  3. Step 3: Cross multiply
    212.40x = 316.90 × 189.30
  4. Step 4: Simplify right side
    212.40x = 59,989.17
  5. Step 5: Solve for x
    x = 59,989.17/212.40
  6. Step 6: Final answer
    x = 282.43

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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.