Answer: 
Step-by-step explanation:
The formula for area of a triangle is 
Now we have to isolate for w.
First multiply by the 2 which is the reciprocal of 1/2 to cancel it out.

Now divide by h to isolate w.
For number 12 the answer is 15.36
4
search up math vvay for more explantion also paste this in there
Error = 60-50/50 × 100
= 10/50 × 100
= 20 %
To multiply mix numbers and a normal fractions you make the mix number into a improper fraction. To do that you multiply the bottom and add the top. Here are the answers:
1/2 x 5 1/2 = 2 3/4
3 3/4 x 1/2 = 1 7/8
1/2 x 3 1/3 = 1 1/6
3/4 x 3 1/6 = 3 1/8
2/1 x 1 1/7 = 2 2/3