Home / 309.19-679.31

Finding the Third Proportional to 309.19 and 679.31

Calculator

Solution

The third proportional to 309.19 and 679.31 is: 1,492.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.19 : 679.31 = 679.31 : x
  2. Step 2: Convert to fraction form
    309.19/679.31 = 679.31/x
  3. Step 3: Cross multiply
    309.19x = 679.31 × 679.31
  4. Step 4: Simplify right side
    309.19x = 461,465.47
  5. Step 5: Solve for x
    x = 461,465.47/309.19
  6. Step 6: Final answer
    x = 1,492.51

Related Problems

Find third proportional to 154.59 and 339.66
Half scale
Find third proportional to 618.38 and 1,358.63
Double scale
Find third proportional to 311 and 684
Similar ratio
Find third proportional to 463.78 and 1,018.97
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.