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Finding the Fourth Proportional to 115.08, 172.20 and 90.84

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Solution

The fourth proportional to 115.08, 172.20 and 90.84 is: 135.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.08 : 172.20 = 90.84 : x
  2. Step 2: Convert to fraction form
    115.08/172.20 = 90.84/x
  3. Step 3: Cross multiply
    115.08x = 172.20 × 90.84
  4. Step 4: Simplify right side
    115.08x = 15,642.65
  5. Step 5: Solve for x
    x = 15,642.65/115.08
  6. Step 6: Final answer
    x = 135.93

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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.