Home / 7,121.80-9,828.52-3,978.20

Finding the Fourth Proportional to 7,121.80, 9,828.52 and 3,978.20

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Solution

The fourth proportional to 7,121.80, 9,828.52 and 3,978.20 is: 5,490.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    7,121.80 : 9,828.52 = 3,978.20 : x
  2. Step 2: Convert to fraction form
    7,121.80/9,828.52 = 3,978.20/x
  3. Step 3: Cross multiply
    7,121.80x = 9,828.52 × 3,978.20
  4. Step 4: Simplify right side
    7,121.80x = 39,099,818.26
  5. Step 5: Solve for x
    x = 39,099,818.26/7,121.80
  6. Step 6: Final answer
    x = 5,490.16

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1.5x scale

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.