Home / 1,315.92-1,971.20-820.70

Finding the Fourth Proportional to 1,315.92, 1,971.20 and 820.70

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Solution

The fourth proportional to 1,315.92, 1,971.20 and 820.70 is: 1,229.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,315.92 : 1,971.20 = 820.70 : x
  2. Step 2: Convert to fraction form
    1,315.92/1,971.20 = 820.70/x
  3. Step 3: Cross multiply
    1,315.92x = 1,971.20 × 820.70
  4. Step 4: Simplify right side
    1,315.92x = 1,617,763.84
  5. Step 5: Solve for x
    x = 1,617,763.84/1,315.92
  6. Step 6: Final answer
    x = 1,229.38

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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.