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Finding the Fourth Proportional to 115.32, 172.80 and 91.32

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Solution

The fourth proportional to 115.32, 172.80 and 91.32 is: 136.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.32 : 172.80 = 91.32 : x
  2. Step 2: Convert to fraction form
    115.32/172.80 = 91.32/x
  3. Step 3: Cross multiply
    115.32x = 172.80 × 91.32
  4. Step 4: Simplify right side
    115.32x = 15,780.10
  5. Step 5: Solve for x
    x = 15,780.10/115.32
  6. Step 6: Final answer
    x = 136.84

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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.