Home / 640.69-721.69

Finding the Third Proportional to 640.69 and 721.69

Calculator

Solution

The third proportional to 640.69 and 721.69 is: 812.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.69 : 721.69 = 721.69 : x
  2. Step 2: Convert to fraction form
    640.69/721.69 = 721.69/x
  3. Step 3: Cross multiply
    640.69x = 721.69 × 721.69
  4. Step 4: Simplify right side
    640.69x = 520,832.85
  5. Step 5: Solve for x
    x = 520,832.85/640.69
  6. Step 6: Final answer
    x = 812.93

Related Problems

Find third proportional to 320.34 and 360.84
Half scale
Find third proportional to 1,281.38 and 1,443.38
Double scale
Find third proportional to 643 and 724
Similar ratio
Find third proportional to 961.03 and 1,082.53
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.13) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.