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Finding the Fourth Proportional to 785.45, 1,178.21 and 265.40

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Solution

The fourth proportional to 785.45, 1,178.21 and 265.40 is: 398.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.45 : 1,178.21 = 265.40 : x
  2. Step 2: Convert to fraction form
    785.45/1,178.21 = 265.40/x
  3. Step 3: Cross multiply
    785.45x = 1,178.21 × 265.40
  4. Step 4: Simplify right side
    785.45x = 312,700.54
  5. Step 5: Solve for x
    x = 312,700.54/785.45
  6. Step 6: Final answer
    x = 398.12

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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.