Home / 1,121.12-1,680.54-428.30

Finding the Fourth Proportional to 1,121.12, 1,680.54 and 428.30

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Solution

The fourth proportional to 1,121.12, 1,680.54 and 428.30 is: 642.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.12 : 1,680.54 = 428.30 : x
  2. Step 2: Convert to fraction form
    1,121.12/1,680.54 = 428.30/x
  3. Step 3: Cross multiply
    1,121.12x = 1,680.54 × 428.30
  4. Step 4: Simplify right side
    1,121.12x = 719,775.28
  5. Step 5: Solve for x
    x = 719,775.28/1,121.12
  6. Step 6: Final answer
    x = 642.01

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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.