Home / 75-128

Finding the Third Proportional to 75 and 128

Calculator

Solution

The third proportional to 75 and 128 is: 218.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    75 : 128 = 128 : x
  2. Step 2: Convert to fraction form
    75/128 = 128/x
  3. Step 3: Cross multiply
    75x = 128 × 128
  4. Step 4: Simplify right side
    75x = 16,384
  5. Step 5: Solve for x
    x = 16,384/75
  6. Step 6: Final answer
    x = 218.45

Related Problems

Find third proportional to 37.50 and 64
Half scale
Find third proportional to 150 and 256
Double scale
Find third proportional to 77 and 131
Similar ratio
Find third proportional to 112.50 and 192
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.71) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.