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Finding the Fourth Proportional to 518.40, 777.20 and 287.15

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Solution

The fourth proportional to 518.40, 777.20 and 287.15 is: 430.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.40 : 777.20 = 287.15 : x
  2. Step 2: Convert to fraction form
    518.40/777.20 = 287.15/x
  3. Step 3: Cross multiply
    518.40x = 777.20 × 287.15
  4. Step 4: Simplify right side
    518.40x = 223,167.66
  5. Step 5: Solve for x
    x = 223,167.66/518.40
  6. Step 6: Final answer
    x = 430.49

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Similar ratio
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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.