Please help me I really need it

15 grams .

Step-by-step explanation:

We need to multiply the percentage as a decimal (0.30) with the amount of chocolate (50 g):

0.30*50 = 15 g

There are 15 grams of cocoa in the chocolate bar.  

Work Shown:

30% = 30/100 = 0.30

30% of 50 = 0.30*50 = 15

Here's another way to think about it: If we had 100 grams of chocolate and 30% are cocoa, then we have 30 grams of cocoa by definition of what percentage means. Divide the 100 in half to get 50, so we'll have to divide the 30 in half to get 15.

where is the triangle?