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Finding the Fourth Proportional to 289.08, 399.15 and 172.80

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Solution

The fourth proportional to 289.08, 399.15 and 172.80 is: 238.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.08 : 399.15 = 172.80 : x
  2. Step 2: Convert to fraction form
    289.08/399.15 = 172.80/x
  3. Step 3: Cross multiply
    289.08x = 399.15 × 172.80
  4. Step 4: Simplify right side
    289.08x = 68,973.12
  5. Step 5: Solve for x
    x = 68,973.12/289.08
  6. Step 6: Final answer
    x = 238.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.