Home / 129.78-177.96-115.20

Finding the Fourth Proportional to 129.78, 177.96 and 115.20

Calculator

Solution

The fourth proportional to 129.78, 177.96 and 115.20 is: 157.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.78 : 177.96 = 115.20 : x
  2. Step 2: Convert to fraction form
    129.78/177.96 = 115.20/x
  3. Step 3: Cross multiply
    129.78x = 177.96 × 115.20
  4. Step 4: Simplify right side
    129.78x = 20,500.99
  5. Step 5: Solve for x
    x = 20,500.99/129.78
  6. Step 6: Final answer
    x = 157.97

Related Problems

Find fourth proportional to 64.89, 88.98 and 57.60
Half scale
Find fourth proportional to 259.56, 355.92 and 230.40
Double scale
Find fourth proportional to 130.78, 179.33 and 116.20
Similar ratio
Find fourth proportional to 194.67, 266.94 and 172.80
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.