Home / 20,772.80-31,159.20-12,478.40

Finding the Fourth Proportional to 20,772.80, 31,159.20 and 12,478.40

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Solution

The fourth proportional to 20,772.80, 31,159.20 and 12,478.40 is: 18,717.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,772.80 : 31,159.20 = 12,478.40 : x
  2. Step 2: Convert to fraction form
    20,772.80/31,159.20 = 12,478.40/x
  3. Step 3: Cross multiply
    20,772.80x = 31,159.20 × 12,478.40
  4. Step 4: Simplify right side
    20,772.80x = 388,816,961.28
  5. Step 5: Solve for x
    x = 388,816,961.28/20,772.80
  6. Step 6: Final answer
    x = 18,717.60

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1.5x scale

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.