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Finding the Fourth Proportional to 115.20, 172.50 and 66.88

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Solution

The fourth proportional to 115.20, 172.50 and 66.88 is: 100.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.20 : 172.50 = 66.88 : x
  2. Step 2: Convert to fraction form
    115.20/172.50 = 66.88/x
  3. Step 3: Cross multiply
    115.20x = 172.50 × 66.88
  4. Step 4: Simplify right side
    115.20x = 11,536.80
  5. Step 5: Solve for x
    x = 11,536.80/115.20
  6. Step 6: Final answer
    x = 100.15

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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.