Home / 480.75-721.25-138.75

Finding the Fourth Proportional to 480.75, 721.25 and 138.75

Calculator

Solution

The fourth proportional to 480.75, 721.25 and 138.75 is: 208.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    480.75 : 721.25 = 138.75 : x
  2. Step 2: Convert to fraction form
    480.75/721.25 = 138.75/x
  3. Step 3: Cross multiply
    480.75x = 721.25 × 138.75
  4. Step 4: Simplify right side
    480.75x = 100,072.74
  5. Step 5: Solve for x
    x = 100,072.74/480.75
  6. Step 6: Final answer
    x = 208.16

Related Problems

Find fourth proportional to 240.38, 360.62 and 69.38
Half scale
Find fourth proportional to 961.50, 1,442.49 and 277.50
Double scale
Find fourth proportional to 481.75, 722.75 and 139.75
Similar ratio
Find fourth proportional to 721.13, 1,081.87 and 208.13
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.