Home / 128-321

Finding the Third Proportional to 128 and 321

Calculator

Solution

The third proportional to 128 and 321 is: 805.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    128 : 321 = 321 : x
  2. Step 2: Convert to fraction form
    128/321 = 321/x
  3. Step 3: Cross multiply
    128x = 321 × 321
  4. Step 4: Simplify right side
    128x = 103,041
  5. Step 5: Solve for x
    x = 103,041/128
  6. Step 6: Final answer
    x = 805.01

Related Problems

Find third proportional to 64 and 160.50
Half scale
Find third proportional to 256 and 642
Double scale
Find third proportional to 130 and 326
Similar ratio
Find third proportional to 192 and 481.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.