Home / 1,315.20-1,972.56-390.72

Finding the Fourth Proportional to 1,315.20, 1,972.56 and 390.72

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Solution

The fourth proportional to 1,315.20, 1,972.56 and 390.72 is: 586.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,315.20 : 1,972.56 = 390.72 : x
  2. Step 2: Convert to fraction form
    1,315.20/1,972.56 = 390.72/x
  3. Step 3: Cross multiply
    1,315.20x = 1,972.56 × 390.72
  4. Step 4: Simplify right side
    1,315.20x = 770,718.64
  5. Step 5: Solve for x
    x = 770,718.64/1,315.20
  6. Step 6: Final answer
    x = 586.01

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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.