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Finding the Fourth Proportional to 518.40, 712.80 and 502.20

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Solution

The fourth proportional to 518.40, 712.80 and 502.20 is: 690.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.40 : 712.80 = 502.20 : x
  2. Step 2: Convert to fraction form
    518.40/712.80 = 502.20/x
  3. Step 3: Cross multiply
    518.40x = 712.80 × 502.20
  4. Step 4: Simplify right side
    518.40x = 357,968.16
  5. Step 5: Solve for x
    x = 357,968.16/518.40
  6. Step 6: Final answer
    x = 690.53

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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.