Home / 1,412.40-2,118.60-721.20

Finding the Fourth Proportional to 1,412.40, 2,118.60 and 721.20

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Solution

The fourth proportional to 1,412.40, 2,118.60 and 721.20 is: 1,081.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,412.40 : 2,118.60 = 721.20 : x
  2. Step 2: Convert to fraction form
    1,412.40/2,118.60 = 721.20/x
  3. Step 3: Cross multiply
    1,412.40x = 2,118.60 × 721.20
  4. Step 4: Simplify right side
    1,412.40x = 1,527,934.32
  5. Step 5: Solve for x
    x = 1,527,934.32/1,412.40
  6. Step 6: Final answer
    x = 1,081.80

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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.