Home / 131.15-180.90-78.65

Finding the Fourth Proportional to 131.15, 180.90 and 78.65

Calculator

Solution

The fourth proportional to 131.15, 180.90 and 78.65 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.15 : 180.90 = 78.65 : x
  2. Step 2: Convert to fraction form
    131.15/180.90 = 78.65/x
  3. Step 3: Cross multiply
    131.15x = 180.90 × 78.65
  4. Step 4: Simplify right side
    131.15x = 14,228.24
  5. Step 5: Solve for x
    x = 14,228.24/131.15
  6. Step 6: Final answer
    x = 108.49

Related Problems

Find fourth proportional to 65.57, 90.45 and 39.33
Half scale
Find fourth proportional to 262.29, 361.80 and 157.31
Double scale
Find fourth proportional to 132.15, 182.28 and 79.65
Similar ratio
Find fourth proportional to 196.72, 271.35 and 117.98
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.