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Finding the Fourth Proportional to 305.47, 421.55 and 172.72

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Solution

The fourth proportional to 305.47, 421.55 and 172.72 is: 238.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.47 : 421.55 = 172.72 : x
  2. Step 2: Convert to fraction form
    305.47/421.55 = 172.72/x
  3. Step 3: Cross multiply
    305.47x = 421.55 × 172.72
  4. Step 4: Simplify right side
    305.47x = 72,808.01
  5. Step 5: Solve for x
    x = 72,808.01/305.47
  6. Step 6: Final answer
    x = 238.35

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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.