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Finding the Fourth Proportional to 145.29, 217.86 and 76.80

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Solution

The fourth proportional to 145.29, 217.86 and 76.80 is: 115.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.29 : 217.86 = 76.80 : x
  2. Step 2: Convert to fraction form
    145.29/217.86 = 76.80/x
  3. Step 3: Cross multiply
    145.29x = 217.86 × 76.80
  4. Step 4: Simplify right side
    145.29x = 16,731.65
  5. Step 5: Solve for x
    x = 16,731.65/145.29
  6. Step 6: Final answer
    x = 115.16

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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.