Home / 811.70-1,138-811.70

Finding the Fourth Proportional to 811.70, 1,138 and 811.70

Calculator

Solution

The fourth proportional to 811.70, 1,138 and 811.70 is: 1,138

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.70 : 1,138 = 811.70 : x
  2. Step 2: Convert to fraction form
    811.70/1,138 = 811.70/x
  3. Step 3: Cross multiply
    811.70x = 1,138 × 811.70
  4. Step 4: Simplify right side
    811.70x = 923,714.60
  5. Step 5: Solve for x
    x = 923,714.60/811.70
  6. Step 6: Final answer
    x = 1,138

Related Problems

Find fourth proportional to 405.85, 569 and 405.85
Half scale
Find fourth proportional to 1,623.40, 2,276 and 1,623.40
Double scale
Find fourth proportional to 812.70, 1,139.40 and 812.70
Similar ratio
Find fourth proportional to 1,217.55, 1,707 and 1,217.55
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.40) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.