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Finding the Fourth Proportional to 114.78, 172.20 and 72

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Solution

The fourth proportional to 114.78, 172.20 and 72 is: 108.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    114.78 : 172.20 = 72 : x
  2. Step 2: Convert to fraction form
    114.78/172.20 = 72/x
  3. Step 3: Cross multiply
    114.78x = 172.20 × 72
  4. Step 4: Simplify right side
    114.78x = 12,398.40
  5. Step 5: Solve for x
    x = 12,398.40/114.78
  6. Step 6: Final answer
    x = 108.02

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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.