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Finding the Fourth Proportional to 210.72, 316.28 and 138.63

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Solution

The fourth proportional to 210.72, 316.28 and 138.63 is: 208.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.72 : 316.28 = 138.63 : x
  2. Step 2: Convert to fraction form
    210.72/316.28 = 138.63/x
  3. Step 3: Cross multiply
    210.72x = 316.28 × 138.63
  4. Step 4: Simplify right side
    210.72x = 43,845.90
  5. Step 5: Solve for x
    x = 43,845.90/210.72
  6. Step 6: Final answer
    x = 208.08

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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.