Home / 320.70-480.69-138.20

Finding the Fourth Proportional to 320.70, 480.69 and 138.20

Calculator

Solution

The fourth proportional to 320.70, 480.69 and 138.20 is: 207.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.70 : 480.69 = 138.20 : x
  2. Step 2: Convert to fraction form
    320.70/480.69 = 138.20/x
  3. Step 3: Cross multiply
    320.70x = 480.69 × 138.20
  4. Step 4: Simplify right side
    320.70x = 66,431.36
  5. Step 5: Solve for x
    x = 66,431.36/320.70
  6. Step 6: Final answer
    x = 207.14

Related Problems

Find fourth proportional to 160.35, 240.35 and 69.10
Half scale
Find fourth proportional to 641.40, 961.38 and 276.40
Double scale
Find fourth proportional to 321.70, 482.19 and 139.20
Similar ratio
Find fourth proportional to 481.05, 721.04 and 207.30
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.