Home / 381-505

Finding the Third Proportional to 381 and 505

Calculator

Solution

The third proportional to 381 and 505 is: 669.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    381 : 505 = 505 : x
  2. Step 2: Convert to fraction form
    381/505 = 505/x
  3. Step 3: Cross multiply
    381x = 505 × 505
  4. Step 4: Simplify right side
    381x = 255,025
  5. Step 5: Solve for x
    x = 255,025/381
  6. Step 6: Final answer
    x = 669.36

Related Problems

Find third proportional to 190.50 and 252.50
Half scale
Find third proportional to 762 and 1,010
Double scale
Find third proportional to 383 and 508
Similar ratio
Find third proportional to 571.50 and 757.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.