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Finding the Fourth Proportional to 261.93, 393.78 and 211.20

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Solution

The fourth proportional to 261.93, 393.78 and 211.20 is: 317.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.93 : 393.78 = 211.20 : x
  2. Step 2: Convert to fraction form
    261.93/393.78 = 211.20/x
  3. Step 3: Cross multiply
    261.93x = 393.78 × 211.20
  4. Step 4: Simplify right side
    261.93x = 83,166.34
  5. Step 5: Solve for x
    x = 83,166.34/261.93
  6. Step 6: Final answer
    x = 317.51

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.