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Finding the Fourth Proportional to 152.72, 210.72 and 87.20

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Solution

The fourth proportional to 152.72, 210.72 and 87.20 is: 120.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    152.72 : 210.72 = 87.20 : x
  2. Step 2: Convert to fraction form
    152.72/210.72 = 87.20/x
  3. Step 3: Cross multiply
    152.72x = 210.72 × 87.20
  4. Step 4: Simplify right side
    152.72x = 18,373.73
  5. Step 5: Solve for x
    x = 18,373.73/152.72
  6. Step 6: Final answer
    x = 120.31

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.