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Finding the Fourth Proportional to 780.42, 1,077.28 and 518.80

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Solution

The fourth proportional to 780.42, 1,077.28 and 518.80 is: 716.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.42 : 1,077.28 = 518.80 : x
  2. Step 2: Convert to fraction form
    780.42/1,077.28 = 518.80/x
  3. Step 3: Cross multiply
    780.42x = 1,077.28 × 518.80
  4. Step 4: Simplify right side
    780.42x = 558,892.86
  5. Step 5: Solve for x
    x = 558,892.86/780.42
  6. Step 6: Final answer
    x = 716.14

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.