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Finding the Fourth Proportional to 345.21, 517.49 and 128.63

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Solution

The fourth proportional to 345.21, 517.49 and 128.63 is: 192.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.21 : 517.49 = 128.63 : x
  2. Step 2: Convert to fraction form
    345.21/517.49 = 128.63/x
  3. Step 3: Cross multiply
    345.21x = 517.49 × 128.63
  4. Step 4: Simplify right side
    345.21x = 66,561.51
  5. Step 5: Solve for x
    x = 66,561.51/345.21
  6. Step 6: Final answer
    x = 192.81

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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.