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Finding the Fourth Proportional to 312.42, 431.47 and 278.06

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Solution

The fourth proportional to 312.42, 431.47 and 278.06 is: 384.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.42 : 431.47 = 278.06 : x
  2. Step 2: Convert to fraction form
    312.42/431.47 = 278.06/x
  3. Step 3: Cross multiply
    312.42x = 431.47 × 278.06
  4. Step 4: Simplify right side
    312.42x = 119,973.17
  5. Step 5: Solve for x
    x = 119,973.17/312.42
  6. Step 6: Final answer
    x = 384.02

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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.