Home / 228.37-315.11-128.78

Finding the Fourth Proportional to 228.37, 315.11 and 128.78

Calculator

Solution

The fourth proportional to 228.37, 315.11 and 128.78 is: 177.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    228.37 : 315.11 = 128.78 : x
  2. Step 2: Convert to fraction form
    228.37/315.11 = 128.78/x
  3. Step 3: Cross multiply
    228.37x = 315.11 × 128.78
  4. Step 4: Simplify right side
    228.37x = 40,579.44
  5. Step 5: Solve for x
    x = 40,579.44/228.37
  6. Step 6: Final answer
    x = 177.70

Related Problems

Find fourth proportional to 114.18, 157.56 and 64.39
Half scale
Find fourth proportional to 456.73, 630.23 and 257.55
Double scale
Find fourth proportional to 229.37, 316.49 and 129.78
Similar ratio
Find fourth proportional to 342.55, 472.67 and 193.17
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.