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Finding the Fourth Proportional to 390.72, 585.91 and 143.93

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Solution

The fourth proportional to 390.72, 585.91 and 143.93 is: 215.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.72 : 585.91 = 143.93 : x
  2. Step 2: Convert to fraction form
    390.72/585.91 = 143.93/x
  3. Step 3: Cross multiply
    390.72x = 585.91 × 143.93
  4. Step 4: Simplify right side
    390.72x = 84,326.74
  5. Step 5: Solve for x
    x = 84,326.74/390.72
  6. Step 6: Final answer
    x = 215.82

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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.