Home / 104.90-157.31-68.78

Finding the Fourth Proportional to 104.90, 157.31 and 68.78

Calculator

Solution

The fourth proportional to 104.90, 157.31 and 68.78 is: 103.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.90 : 157.31 = 68.78 : x
  2. Step 2: Convert to fraction form
    104.90/157.31 = 68.78/x
  3. Step 3: Cross multiply
    104.90x = 157.31 × 68.78
  4. Step 4: Simplify right side
    104.90x = 10,820.09
  5. Step 5: Solve for x
    x = 10,820.09/104.90
  6. Step 6: Final answer
    x = 103.15

Related Problems

Find fourth proportional to 52.45, 78.65 and 34.39
Half scale
Find fourth proportional to 209.79, 314.62 and 137.57
Double scale
Find fourth proportional to 105.90, 158.81 and 69.78
Similar ratio
Find fourth proportional to 157.34, 235.96 and 103.17
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.