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Finding the Fourth Proportional to 210.79, 316.32 and 138.70

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Solution

The fourth proportional to 210.79, 316.32 and 138.70 is: 208.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.79 : 316.32 = 138.70 : x
  2. Step 2: Convert to fraction form
    210.79/316.32 = 138.70/x
  3. Step 3: Cross multiply
    210.79x = 316.32 × 138.70
  4. Step 4: Simplify right side
    210.79x = 43,873.58
  5. Step 5: Solve for x
    x = 43,873.58/210.79
  6. Step 6: Final answer
    x = 208.14

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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.