Home / 88.40-121.92-72

Finding the Fourth Proportional to 88.40, 121.92 and 72

Calculator

Solution

The fourth proportional to 88.40, 121.92 and 72 is: 99.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.40 : 121.92 = 72 : x
  2. Step 2: Convert to fraction form
    88.40/121.92 = 72/x
  3. Step 3: Cross multiply
    88.40x = 121.92 × 72
  4. Step 4: Simplify right side
    88.40x = 8,778.24
  5. Step 5: Solve for x
    x = 8,778.24/88.40
  6. Step 6: Final answer
    x = 99.30

Related Problems

Find fourth proportional to 44.20, 60.96 and 36
Half scale
Find fourth proportional to 176.80, 243.84 and 144
Double scale
Find fourth proportional to 89.40, 123.30 and 73
Similar ratio
Find fourth proportional to 132.60, 182.88 and 108
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.