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Finding the Third Proportional to 30 and 72

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Solution

The third proportional to 30 and 72 is: 172.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    30 : 72 = 72 : x
  2. Step 2: Convert to fraction form
    30/72 = 72/x
  3. Step 3: Cross multiply
    30x = 72 × 72
  4. Step 4: Simplify right side
    30x = 5,184
  5. Step 5: Solve for x
    x = 5,184/30
  6. Step 6: Final answer
    x = 172.80

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Why These Related Problems?

These problems maintain the same ratio (2.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.