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Finding the Fourth Proportional to 1,287.50, 1,931.34 and 518

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Solution

The fourth proportional to 1,287.50, 1,931.34 and 518 is: 777.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.50 : 1,931.34 = 518 : x
  2. Step 2: Convert to fraction form
    1,287.50/1,931.34 = 518/x
  3. Step 3: Cross multiply
    1,287.50x = 1,931.34 × 518
  4. Step 4: Simplify right side
    1,287.50x = 1,000,434.12
  5. Step 5: Solve for x
    x = 1,000,434.12/1,287.50
  6. Step 6: Final answer
    x = 777.04

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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.