Home / 115.75-128.75

Finding the Third Proportional to 115.75 and 128.75

Calculator

Solution

The third proportional to 115.75 and 128.75 is: 143.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.75 : 128.75 = 128.75 : x
  2. Step 2: Convert to fraction form
    115.75/128.75 = 128.75/x
  3. Step 3: Cross multiply
    115.75x = 128.75 × 128.75
  4. Step 4: Simplify right side
    115.75x = 16,576.56
  5. Step 5: Solve for x
    x = 16,576.56/115.75
  6. Step 6: Final answer
    x = 143.21

Related Problems

Find third proportional to 57.88 and 64.38
Half scale
Find third proportional to 231.50 and 257.50
Double scale
Find third proportional to 118 and 131
Similar ratio
Find third proportional to 173.63 and 193.13
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.