Home / 113.55-156.78-72.21

Finding the Fourth Proportional to 113.55, 156.78 and 72.21

Calculator

Solution

The fourth proportional to 113.55, 156.78 and 72.21 is: 99.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.55 : 156.78 = 72.21 : x
  2. Step 2: Convert to fraction form
    113.55/156.78 = 72.21/x
  3. Step 3: Cross multiply
    113.55x = 156.78 × 72.21
  4. Step 4: Simplify right side
    113.55x = 11,321.08
  5. Step 5: Solve for x
    x = 11,321.08/113.55
  6. Step 6: Final answer
    x = 99.70

Related Problems

Find fourth proportional to 56.78, 78.39 and 36.11
Half scale
Find fourth proportional to 227.10, 313.56 and 144.42
Double scale
Find fourth proportional to 114.55, 158.16 and 73.21
Similar ratio
Find fourth proportional to 170.33, 235.17 and 108.32
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.