Answer: 
Step-by-step explanation:
Equilateral triangle has equal sides, let the side be
, then the perimeter is 
Therefore:



To find the altitude , we will apply Pythagoras theorem , that is

Therefore:



take the square root of both sides

Answer:
5x+120
Step-by-step explanation:
first you add the 2x x and x and x that would get you 5x and then add the 20 and 10 and 80 that would get you 120
Area of triangle = 1/2 x base x height
so old triangle we have 1/2 x b x h = 48
new triangle has base 3 times as long and height is half as long
so we would get:
1/2 x (3B) x (1/2H) = area
rewrite as 1/2 x 3/2 x b x H = area
divide by original are os 1/2 x b x h and you end up with 3/2
so new area = 3/2 x old area
new area = 3/2 * 48 = 72 square inches
Answer:
The Answer is: 63°
Step-by-step explanation:
The angle 117° is the key information. Across the line, the angle 117° is part of the 180° across the line. Angle RMN is equal to 180° - 117° = 63°