Home / 118.90-178.08-78.31

Finding the Fourth Proportional to 118.90, 178.08 and 78.31

Calculator

Solution

The fourth proportional to 118.90, 178.08 and 78.31 is: 117.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    118.90 : 178.08 = 78.31 : x
  2. Step 2: Convert to fraction form
    118.90/178.08 = 78.31/x
  3. Step 3: Cross multiply
    118.90x = 178.08 × 78.31
  4. Step 4: Simplify right side
    118.90x = 13,945.44
  5. Step 5: Solve for x
    x = 13,945.44/118.90
  6. Step 6: Final answer
    x = 117.29

Related Problems

Find fourth proportional to 59.45, 89.04 and 39.16
Half scale
Find fourth proportional to 237.80, 356.16 and 156.62
Double scale
Find fourth proportional to 119.90, 179.58 and 79.31
Similar ratio
Find fourth proportional to 178.35, 267.12 and 117.47
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.