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Finding the Fourth Proportional to 431.79, 647.88 and 258.45

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Solution

The fourth proportional to 431.79, 647.88 and 258.45 is: 387.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.79 : 647.88 = 258.45 : x
  2. Step 2: Convert to fraction form
    431.79/647.88 = 258.45/x
  3. Step 3: Cross multiply
    431.79x = 647.88 × 258.45
  4. Step 4: Simplify right side
    431.79x = 167,444.59
  5. Step 5: Solve for x
    x = 167,444.59/431.79
  6. Step 6: Final answer
    x = 387.79

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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.