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Finding the Fourth Proportional to 172.80, 259.20 and 142.80

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Solution

The fourth proportional to 172.80, 259.20 and 142.80 is: 214.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.80 : 259.20 = 142.80 : x
  2. Step 2: Convert to fraction form
    172.80/259.20 = 142.80/x
  3. Step 3: Cross multiply
    172.80x = 259.20 × 142.80
  4. Step 4: Simplify right side
    172.80x = 37,013.76
  5. Step 5: Solve for x
    x = 37,013.76/172.80
  6. Step 6: Final answer
    x = 214.20

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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.