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Finding the Fourth Proportional to 310.55, 428.40 and 212.40

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Solution

The fourth proportional to 310.55, 428.40 and 212.40 is: 293.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.55 : 428.40 = 212.40 : x
  2. Step 2: Convert to fraction form
    310.55/428.40 = 212.40/x
  3. Step 3: Cross multiply
    310.55x = 428.40 × 212.40
  4. Step 4: Simplify right side
    310.55x = 90,992.16
  5. Step 5: Solve for x
    x = 90,992.16/310.55
  6. Step 6: Final answer
    x = 293.01

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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.