Home / 12,890.88-17,792.64-7,920

Finding the Fourth Proportional to 12,890.88, 17,792.64 and 7,920

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Solution

The fourth proportional to 12,890.88, 17,792.64 and 7,920 is: 10,931.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    12,890.88 : 17,792.64 = 7,920 : x
  2. Step 2: Convert to fraction form
    12,890.88/17,792.64 = 7,920/x
  3. Step 3: Cross multiply
    12,890.88x = 17,792.64 × 7,920
  4. Step 4: Simplify right side
    12,890.88x = 140,917,708.80
  5. Step 5: Solve for x
    x = 140,917,708.80/12,890.88
  6. Step 6: Final answer
    x = 10,931.58

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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.