Home / 1,421.65-2,129.38-689.70

Finding the Fourth Proportional to 1,421.65, 2,129.38 and 689.70

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Solution

The fourth proportional to 1,421.65, 2,129.38 and 689.70 is: 1,033.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.65 : 2,129.38 = 689.70 : x
  2. Step 2: Convert to fraction form
    1,421.65/2,129.38 = 689.70/x
  3. Step 3: Cross multiply
    1,421.65x = 2,129.38 × 689.70
  4. Step 4: Simplify right side
    1,421.65x = 1,468,633.39
  5. Step 5: Solve for x
    x = 1,468,633.39/1,421.65
  6. Step 6: Final answer
    x = 1,033.05

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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.