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Finding the Fourth Proportional to 780.16, 1,171.20 and 492.80

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Solution

The fourth proportional to 780.16, 1,171.20 and 492.80 is: 739.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.16 : 1,171.20 = 492.80 : x
  2. Step 2: Convert to fraction form
    780.16/1,171.20 = 492.80/x
  3. Step 3: Cross multiply
    780.16x = 1,171.20 × 492.80
  4. Step 4: Simplify right side
    780.16x = 577,167.36
  5. Step 5: Solve for x
    x = 577,167.36/780.16
  6. Step 6: Final answer
    x = 739.81

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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.