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Finding the Fourth Proportional to 111.65, 153.97 and 87.10

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Solution

The fourth proportional to 111.65, 153.97 and 87.10 is: 120.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.65 : 153.97 = 87.10 : x
  2. Step 2: Convert to fraction form
    111.65/153.97 = 87.10/x
  3. Step 3: Cross multiply
    111.65x = 153.97 × 87.10
  4. Step 4: Simplify right side
    111.65x = 13,410.18
  5. Step 5: Solve for x
    x = 13,410.18/111.65
  6. Step 6: Final answer
    x = 120.11

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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.