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Finding the Fourth Proportional to 305.51, 421.57 and 172.72

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Solution

The fourth proportional to 305.51, 421.57 and 172.72 is: 238.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.51 : 421.57 = 172.72 : x
  2. Step 2: Convert to fraction form
    305.51/421.57 = 172.72/x
  3. Step 3: Cross multiply
    305.51x = 421.57 × 172.72
  4. Step 4: Simplify right side
    305.51x = 72,812.52
  5. Step 5: Solve for x
    x = 72,812.52/305.51
  6. Step 6: Final answer
    x = 238.33

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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.