Home / 138.75-217.50

Finding the Third Proportional to 138.75 and 217.50

Calculator

Solution

The third proportional to 138.75 and 217.50 is: 340.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.75 : 217.50 = 217.50 : x
  2. Step 2: Convert to fraction form
    138.75/217.50 = 217.50/x
  3. Step 3: Cross multiply
    138.75x = 217.50 × 217.50
  4. Step 4: Simplify right side
    138.75x = 47,306.25
  5. Step 5: Solve for x
    x = 47,306.25/138.75
  6. Step 6: Final answer
    x = 340.95

Related Problems

Find third proportional to 69.38 and 108.75
Half scale
Find third proportional to 277.50 and 435
Double scale
Find third proportional to 141 and 221
Similar ratio
Find third proportional to 208.13 and 326.25
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.57) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.