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Finding the Fourth Proportional to 780.65, 1,170.05 and 318.18

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Solution

The fourth proportional to 780.65, 1,170.05 and 318.18 is: 476.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.65 : 1,170.05 = 318.18 : x
  2. Step 2: Convert to fraction form
    780.65/1,170.05 = 318.18/x
  3. Step 3: Cross multiply
    780.65x = 1,170.05 × 318.18
  4. Step 4: Simplify right side
    780.65x = 372,284.92
  5. Step 5: Solve for x
    x = 372,284.92/780.65
  6. Step 6: Final answer
    x = 476.89

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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.