Home / 290.89-436.65-128.71

Finding the Fourth Proportional to 290.89, 436.65 and 128.71

Calculator

Solution

The fourth proportional to 290.89, 436.65 and 128.71 is: 193.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.89 : 436.65 = 128.71 : x
  2. Step 2: Convert to fraction form
    290.89/436.65 = 128.71/x
  3. Step 3: Cross multiply
    290.89x = 436.65 × 128.71
  4. Step 4: Simplify right side
    290.89x = 56,201.22
  5. Step 5: Solve for x
    x = 56,201.22/290.89
  6. Step 6: Final answer
    x = 193.20

Related Problems

Find fourth proportional to 145.45, 218.33 and 64.36
Half scale
Find fourth proportional to 581.78, 873.30 and 257.42
Double scale
Find fourth proportional to 291.89, 438.15 and 129.71
Similar ratio
Find fourth proportional to 436.34, 654.98 and 193.07
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.