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Finding the Fourth Proportional to 312.16, 430.78 and 172.28

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Solution

The fourth proportional to 312.16, 430.78 and 172.28 is: 237.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.16 : 430.78 = 172.28 : x
  2. Step 2: Convert to fraction form
    312.16/430.78 = 172.28/x
  3. Step 3: Cross multiply
    312.16x = 430.78 × 172.28
  4. Step 4: Simplify right side
    312.16x = 74,214.78
  5. Step 5: Solve for x
    x = 74,214.78/312.16
  6. Step 6: Final answer
    x = 237.75

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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.