Home / 686-1,311

Finding the Third Proportional to 686 and 1,311

Calculator

Solution

The third proportional to 686 and 1,311 is: 2,505.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    686 : 1,311 = 1,311 : x
  2. Step 2: Convert to fraction form
    686/1,311 = 1,311/x
  3. Step 3: Cross multiply
    686x = 1,311 × 1,311
  4. Step 4: Simplify right side
    686x = 1,718,721
  5. Step 5: Solve for x
    x = 1,718,721/686
  6. Step 6: Final answer
    x = 2,505.42

Related Problems

Find third proportional to 343 and 655.50
Half scale
Find third proportional to 1,372 and 2,622
Double scale
Find third proportional to 688 and 1,315
Similar ratio
Find third proportional to 1,029 and 1,966.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.91) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.