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Finding the Fourth Proportional to 520.40, 780.60 and 276.80

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Solution

The fourth proportional to 520.40, 780.60 and 276.80 is: 415.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.40 : 780.60 = 276.80 : x
  2. Step 2: Convert to fraction form
    520.40/780.60 = 276.80/x
  3. Step 3: Cross multiply
    520.40x = 780.60 × 276.80
  4. Step 4: Simplify right side
    520.40x = 216,070.08
  5. Step 5: Solve for x
    x = 216,070.08/520.40
  6. Step 6: Final answer
    x = 415.20

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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.