Home / 321.39-482.12-138.80

Finding the Fourth Proportional to 321.39, 482.12 and 138.80

Calculator

Solution

The fourth proportional to 321.39, 482.12 and 138.80 is: 208.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.39 : 482.12 = 138.80 : x
  2. Step 2: Convert to fraction form
    321.39/482.12 = 138.80/x
  3. Step 3: Cross multiply
    321.39x = 482.12 × 138.80
  4. Step 4: Simplify right side
    321.39x = 66,918.26
  5. Step 5: Solve for x
    x = 66,918.26/321.39
  6. Step 6: Final answer
    x = 208.22

Related Problems

Find fourth proportional to 160.70, 241.06 and 69.40
Half scale
Find fourth proportional to 642.78, 964.24 and 277.60
Double scale
Find fourth proportional to 322.39, 483.62 and 139.80
Similar ratio
Find fourth proportional to 482.09, 723.18 and 208.20
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.