Answer:
Use Heron's formula; see below.
Step-by-step explanation:
Use Heron's formula.
Let the sides of the triangle have lengths a, b, and c.


Example:
A triangle has side lengths 3, 4, and 5 units.
Find the area of the triangle.








1/4 the students in study hall (per 7) = 16
16*4 = 64 students in study hall.
<span>Hope I helped! (Pick my answer as brainliest!)</span>
5x-y
=5(3)-1
=15-1
=14
Therefore, the answer is 14.