Kinda late, but do you have the area of the triangle?
Since there is nothing attached for me to help you I looked for a website that can find the answer with an explanation. It is called quickmath it’s like a math calculator . Hopefully that helps you .
Answer:
1/5 is left.
Step-by-step explanation:
Portion remaining after the bar was eaten by his brother = 1 - 1/5 = 4/5.
Portion remaining after John ate 3/4 of this = 4/5 - 3/4* 4/5 = 4/5 - 3/5
= 1/5.