Home / 109-207

Finding the Third Proportional to 109 and 207

Calculator

Solution

The third proportional to 109 and 207 is: 393.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    109 : 207 = 207 : x
  2. Step 2: Convert to fraction form
    109/207 = 207/x
  3. Step 3: Cross multiply
    109x = 207 × 207
  4. Step 4: Simplify right side
    109x = 42,849
  5. Step 5: Solve for x
    x = 42,849/109
  6. Step 6: Final answer
    x = 393.11

Related Problems

Find third proportional to 54.50 and 103.50
Half scale
Find third proportional to 218 and 414
Double scale
Find third proportional to 111 and 211
Similar ratio
Find third proportional to 163.50 and 310.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.90) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.