Home / 111.60-154.16-78.80

Finding the Fourth Proportional to 111.60, 154.16 and 78.80

Calculator

Solution

The fourth proportional to 111.60, 154.16 and 78.80 is: 108.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.60 : 154.16 = 78.80 : x
  2. Step 2: Convert to fraction form
    111.60/154.16 = 78.80/x
  3. Step 3: Cross multiply
    111.60x = 154.16 × 78.80
  4. Step 4: Simplify right side
    111.60x = 12,147.81
  5. Step 5: Solve for x
    x = 12,147.81/111.60
  6. Step 6: Final answer
    x = 108.85

Related Problems

Find fourth proportional to 55.80, 77.08 and 39.40
Half scale
Find fourth proportional to 223.20, 308.32 and 157.60
Double scale
Find fourth proportional to 112.60, 155.54 and 79.80
Similar ratio
Find fourth proportional to 167.40, 231.24 and 118.20
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.