Answer:

Step-by-step explanation:
see the attached figure to better understand the problem
step 1
Find the measure of the vertex angle ∠ABD of an isosceles triangle
we know that
An isosceles triangle has two equal sides and two equal angles
In this problem
----> the angles of the base are equals
Find the measure of the vertex angle ABD
------> the sum of the internal angles of a triangle is equal to 180 degrees
step 2
Find the measure of the angle ∠CBD in the equilateral triangle
we know that
A equilateral triangle has three equal sides and three equal angles
The measure of the internal angle in a equilateral triangle is equal to 60 degrees
so

step 3
Find the measure of the angle ∠ABC
we know that
---> by addition angle postulate
substitute the values


Answer:
I think it's 1,728 millimeters ^3
Answer:
15/18, 0.84, 85%
Step-by-step explanation:
Please let me know if you want me to add an explanation as to why this is the answer. I can definitely do that, I just wouldn’t want to write it if you don’t want me to :)