Home / 311-509

Finding the Third Proportional to 311 and 509

Calculator

Solution

The third proportional to 311 and 509 is: 833.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    311 : 509 = 509 : x
  2. Step 2: Convert to fraction form
    311/509 = 509/x
  3. Step 3: Cross multiply
    311x = 509 × 509
  4. Step 4: Simplify right side
    311x = 259,081
  5. Step 5: Solve for x
    x = 259,081/311
  6. Step 6: Final answer
    x = 833.06

Related Problems

Find third proportional to 155.50 and 254.50
Half scale
Find third proportional to 622 and 1,018
Double scale
Find third proportional to 313 and 512
Similar ratio
Find third proportional to 466.50 and 763.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.64) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.