Answer:

Step-by-step explanation:
we know that
If the triangle of the figure is a regular polygon
then
Is an equilateral triangle
Remember that
The equilateral triangle has three equal sides and three equal interior angles
The measure of each interior angle is 60 degrees
To find the area of the equilateral triangle apply the law of sines

we have that

substitute

Answer
Yes
Explanation
I just know
A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers
Step-by-step explanation:
The doorstop is a triangular prism. volume of the triangular prism is the area of the base times the height
area of the base: 1/2 * 10*6=30cm²
height: 2.5cm
Volume: 30cm²*2.5cm=75cm³
weight: 75cm³*8.6g/cm³=645 grams