Home / 1,315.21-1,972.47-390.55

Finding the Fourth Proportional to 1,315.21, 1,972.47 and 390.55

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Solution

The fourth proportional to 1,315.21, 1,972.47 and 390.55 is: 585.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,315.21 : 1,972.47 = 390.55 : x
  2. Step 2: Convert to fraction form
    1,315.21/1,972.47 = 390.55/x
  3. Step 3: Cross multiply
    1,315.21x = 1,972.47 × 390.55
  4. Step 4: Simplify right side
    1,315.21x = 770,343.23
  5. Step 5: Solve for x
    x = 770,343.23/1,315.21
  6. Step 6: Final answer
    x = 585.72

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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.