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Finding the Fourth Proportional to 780.82, 1,170.92 and 390.50

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Solution

The fourth proportional to 780.82, 1,170.92 and 390.50 is: 585.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.82 : 1,170.92 = 390.50 : x
  2. Step 2: Convert to fraction form
    780.82/1,170.92 = 390.50/x
  3. Step 3: Cross multiply
    780.82x = 1,170.92 × 390.50
  4. Step 4: Simplify right side
    780.82x = 457,244.26
  5. Step 5: Solve for x
    x = 457,244.26/780.82
  6. Step 6: Final answer
    x = 585.59

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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.