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Finding the Fourth Proportional to 145.12, 217.36 and 72.80

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Solution

The fourth proportional to 145.12, 217.36 and 72.80 is: 109.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.12 : 217.36 = 72.80 : x
  2. Step 2: Convert to fraction form
    145.12/217.36 = 72.80/x
  3. Step 3: Cross multiply
    145.12x = 217.36 × 72.80
  4. Step 4: Simplify right side
    145.12x = 15,823.81
  5. Step 5: Solve for x
    x = 15,823.81/145.12
  6. Step 6: Final answer
    x = 109.04

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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.