Home / 139-208

Finding the Third Proportional to 139 and 208

Calculator

Solution

The third proportional to 139 and 208 is: 311.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    139 : 208 = 208 : x
  2. Step 2: Convert to fraction form
    139/208 = 208/x
  3. Step 3: Cross multiply
    139x = 208 × 208
  4. Step 4: Simplify right side
    139x = 43,264
  5. Step 5: Solve for x
    x = 43,264/139
  6. Step 6: Final answer
    x = 311.25

Related Problems

Find third proportional to 69.50 and 104
Half scale
Find third proportional to 278 and 416
Double scale
Find third proportional to 141 and 211
Similar ratio
Find third proportional to 208.50 and 312
1.5x scale

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.