Home / 260.78-391.25-138.95

Finding the Fourth Proportional to 260.78, 391.25 and 138.95

Calculator

Solution

The fourth proportional to 260.78, 391.25 and 138.95 is: 208.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.78 : 391.25 = 138.95 : x
  2. Step 2: Convert to fraction form
    260.78/391.25 = 138.95/x
  3. Step 3: Cross multiply
    260.78x = 391.25 × 138.95
  4. Step 4: Simplify right side
    260.78x = 54,364.19
  5. Step 5: Solve for x
    x = 54,364.19/260.78
  6. Step 6: Final answer
    x = 208.47

Related Problems

Find fourth proportional to 130.39, 195.63 and 69.48
Half scale
Find fourth proportional to 521.56, 782.50 and 277.90
Double scale
Find fourth proportional to 261.78, 392.75 and 139.95
Similar ratio
Find fourth proportional to 391.17, 586.88 and 208.43
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.