Home / 1,287.12-1,929.40-518.16

Finding the Fourth Proportional to 1,287.12, 1,929.40 and 518.16

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Solution

The fourth proportional to 1,287.12, 1,929.40 and 518.16 is: 776.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.12 : 1,929.40 = 518.16 : x
  2. Step 2: Convert to fraction form
    1,287.12/1,929.40 = 518.16/x
  3. Step 3: Cross multiply
    1,287.12x = 1,929.40 × 518.16
  4. Step 4: Simplify right side
    1,287.12x = 999,737.90
  5. Step 5: Solve for x
    x = 999,737.90/1,287.12
  6. Step 6: Final answer
    x = 776.72

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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.