Home / 415.13-643.78

Finding the Third Proportional to 415.13 and 643.78

Calculator

Solution

The third proportional to 415.13 and 643.78 is: 998.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.13 : 643.78 = 643.78 : x
  2. Step 2: Convert to fraction form
    415.13/643.78 = 643.78/x
  3. Step 3: Cross multiply
    415.13x = 643.78 × 643.78
  4. Step 4: Simplify right side
    415.13x = 414,454.30
  5. Step 5: Solve for x
    x = 414,454.30/415.13
  6. Step 6: Final answer
    x = 998.38

Related Problems

Find third proportional to 207.56 and 321.89
Half scale
Find third proportional to 830.25 and 1,287.56
Double scale
Find third proportional to 417 and 647
Similar ratio
Find third proportional to 622.69 and 965.67
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.