Home / 78.75-129.75

Finding the Third Proportional to 78.75 and 129.75

Calculator

Solution

The third proportional to 78.75 and 129.75 is: 213.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.75 : 129.75 = 129.75 : x
  2. Step 2: Convert to fraction form
    78.75/129.75 = 129.75/x
  3. Step 3: Cross multiply
    78.75x = 129.75 × 129.75
  4. Step 4: Simplify right side
    78.75x = 16,835.06
  5. Step 5: Solve for x
    x = 16,835.06/78.75
  6. Step 6: Final answer
    x = 213.78

Related Problems

Find third proportional to 39.38 and 64.88
Half scale
Find third proportional to 157.50 and 259.50
Double scale
Find third proportional to 81 and 133
Similar ratio
Find third proportional to 118.13 and 194.63
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.65) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.