Home / 721-820

Finding the Third Proportional to 721 and 820

Calculator

Solution

The third proportional to 721 and 820 is: 932.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    721 : 820 = 820 : x
  2. Step 2: Convert to fraction form
    721/820 = 820/x
  3. Step 3: Cross multiply
    721x = 820 × 820
  4. Step 4: Simplify right side
    721x = 672,400
  5. Step 5: Solve for x
    x = 672,400/721
  6. Step 6: Final answer
    x = 932.59

Related Problems

Find third proportional to 360.50 and 410
Half scale
Find third proportional to 1,442 and 1,640
Double scale
Find third proportional to 723 and 822
Similar ratio
Find third proportional to 1,081.50 and 1,230
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.14) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.