Home / 1,320.90-1,981.36-1,280.78

Finding the Fourth Proportional to 1,320.90, 1,981.36 and 1,280.78

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Solution

The fourth proportional to 1,320.90, 1,981.36 and 1,280.78 is: 1,921.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,320.90 : 1,981.36 = 1,280.78 : x
  2. Step 2: Convert to fraction form
    1,320.90/1,981.36 = 1,280.78/x
  3. Step 3: Cross multiply
    1,320.90x = 1,981.36 × 1,280.78
  4. Step 4: Simplify right side
    1,320.90x = 2,537,686.26
  5. Step 5: Solve for x
    x = 2,537,686.26/1,320.90
  6. Step 6: Final answer
    x = 1,921.18

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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.