Question

Which is the height of the triangle?
( PIC IS PROVIDE PLS HELP ME)

Answer 1

There is so many ways to calculate height in this case.

Here, you can use one of properties of isosceles triangle, it can be divided into 2 smaller congruent right triangles.

Then Height = sqrt( 100^2 - (120/2)^2) = sqrt(6400) = 80

Answer 2

Answer: 80 meters

This is an isosceles triangle. The dashed line is the height which is perpendicular to the base 120. The height is always perpendicular to the base. The dashed line cuts the base into two equal pieces (this only works for isosceles triangles when you cut at the vertex like this).

So we have two smaller triangles each with a base of 60 and a height of x. Focus on one of the right triangles and use the pythagorean theorem to solve for x.

a^2 + b^2 = c^2

x^2 + (60)^2 = (100)^2

x^2 + 3600 = 10000

x^2 = 10000 - 3600

x^2 = 6400

x = sqrt(6400)

x = 80

Each smaller right triangle has side lengths of 60, 80, 100

Note the ratio 60:80:100 reduces to 3:4:5. A 3-4-5 right triangle is a very common pythagorean primitive.