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Finding the Fourth Proportional to 261.51, 390.44 and 215.96

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Solution

The fourth proportional to 261.51, 390.44 and 215.96 is: 322.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.51 : 390.44 = 215.96 : x
  2. Step 2: Convert to fraction form
    261.51/390.44 = 215.96/x
  3. Step 3: Cross multiply
    261.51x = 390.44 × 215.96
  4. Step 4: Simplify right side
    261.51x = 84,316.39
  5. Step 5: Solve for x
    x = 84,316.39/261.51
  6. Step 6: Final answer
    x = 322.42

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.