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Finding the Fourth Proportional to 153.09, 211.20 and 87.60

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Solution

The fourth proportional to 153.09, 211.20 and 87.60 is: 120.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.09 : 211.20 = 87.60 : x
  2. Step 2: Convert to fraction form
    153.09/211.20 = 87.60/x
  3. Step 3: Cross multiply
    153.09x = 211.20 × 87.60
  4. Step 4: Simplify right side
    153.09x = 18,501.12
  5. Step 5: Solve for x
    x = 18,501.12/153.09
  6. Step 6: Final answer
    x = 120.85

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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.