Home / 1,378.60-2,068.18-720.78

Finding the Fourth Proportional to 1,378.60, 2,068.18 and 720.78

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Solution

The fourth proportional to 1,378.60, 2,068.18 and 720.78 is: 1,081.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.60 : 2,068.18 = 720.78 : x
  2. Step 2: Convert to fraction form
    1,378.60/2,068.18 = 720.78/x
  3. Step 3: Cross multiply
    1,378.60x = 2,068.18 × 720.78
  4. Step 4: Simplify right side
    1,378.60x = 1,490,708.91
  5. Step 5: Solve for x
    x = 1,490,708.91/1,378.60
  6. Step 6: Final answer
    x = 1,081.32

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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.