Home / 121.78-209.53

Finding the Third Proportional to 121.78 and 209.53

Calculator

Solution

The third proportional to 121.78 and 209.53 is: 360.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.78 : 209.53 = 209.53 : x
  2. Step 2: Convert to fraction form
    121.78/209.53 = 209.53/x
  3. Step 3: Cross multiply
    121.78x = 209.53 × 209.53
  4. Step 4: Simplify right side
    121.78x = 43,903.34
  5. Step 5: Solve for x
    x = 43,903.34/121.78
  6. Step 6: Final answer
    x = 360.51

Related Problems

Find third proportional to 60.89 and 104.77
Half scale
Find third proportional to 243.56 and 419.06
Double scale
Find third proportional to 124 and 213
Similar ratio
Find third proportional to 182.67 and 314.30
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.72) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.