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Finding the Fourth Proportional to 115.49, 172.85 and 99.65

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Solution

The fourth proportional to 115.49, 172.85 and 99.65 is: 149.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.49 : 172.85 = 99.65 : x
  2. Step 2: Convert to fraction form
    115.49/172.85 = 99.65/x
  3. Step 3: Cross multiply
    115.49x = 172.85 × 99.65
  4. Step 4: Simplify right side
    115.49x = 17,223.14
  5. Step 5: Solve for x
    x = 17,223.14/115.49
  6. Step 6: Final answer
    x = 149.14

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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.