Home / 398-638

Finding the Third Proportional to 398 and 638

Calculator

Solution

The third proportional to 398 and 638 is: 1,022.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    398 : 638 = 638 : x
  2. Step 2: Convert to fraction form
    398/638 = 638/x
  3. Step 3: Cross multiply
    398x = 638 × 638
  4. Step 4: Simplify right side
    398x = 407,044
  5. Step 5: Solve for x
    x = 407,044/398
  6. Step 6: Final answer
    x = 1,022.72

Related Problems

Find third proportional to 199 and 319
Half scale
Find third proportional to 796 and 1,276
Double scale
Find third proportional to 400 and 641
Similar ratio
Find third proportional to 597 and 957
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.60) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.