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Finding the Fourth Proportional to 780.11, 1,170.20 and 317.66

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Solution

The fourth proportional to 780.11, 1,170.20 and 317.66 is: 476.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.11 : 1,170.20 = 317.66 : x
  2. Step 2: Convert to fraction form
    780.11/1,170.20 = 317.66/x
  3. Step 3: Cross multiply
    780.11x = 1,170.20 × 317.66
  4. Step 4: Simplify right side
    780.11x = 371,718.29
  5. Step 5: Solve for x
    x = 371,718.29/780.11
  6. Step 6: Final answer
    x = 476.50

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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.