Home / 1,387.20-2,075.64-839.78

Finding the Fourth Proportional to 1,387.20, 2,075.64 and 839.78

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Solution

The fourth proportional to 1,387.20, 2,075.64 and 839.78 is: 1,256.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.20 : 2,075.64 = 839.78 : x
  2. Step 2: Convert to fraction form
    1,387.20/2,075.64 = 839.78/x
  3. Step 3: Cross multiply
    1,387.20x = 2,075.64 × 839.78
  4. Step 4: Simplify right side
    1,387.20x = 1,743,080.96
  5. Step 5: Solve for x
    x = 1,743,080.96/1,387.20
  6. Step 6: Final answer
    x = 1,256.55

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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.