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Finding the Fourth Proportional to 780.48, 1,170.23 and 390.02

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Solution

The fourth proportional to 780.48, 1,170.23 and 390.02 is: 584.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.48 : 1,170.23 = 390.02 : x
  2. Step 2: Convert to fraction form
    780.48/1,170.23 = 390.02/x
  3. Step 3: Cross multiply
    780.48x = 1,170.23 × 390.02
  4. Step 4: Simplify right side
    780.48x = 456,405.30
  5. Step 5: Solve for x
    x = 456,405.30/780.48
  6. Step 6: Final answer
    x = 584.78

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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.