45 so the sun can hit directly to the panel
Since the triangle is equilateral, all its angles are equal to 60°
AO is the bisector⇒∠OAD = 30°
AO is the hypotenuse, ∠OAD = 30°⇒
OD=5*2=10m
By the Pythagorean theorem
Answer: A) 
m²
P.S. Hello from Russia and sorry for my bad english :^)
First, solve for the volume (V) of each cylinder by the equation,
V = πd²h / 4
where d and h are diameter and height, respectively. Substituting the given values,
V = π(6.19 cm)² x (6 cm) / 4 = 180.56 cm³
To determine the number of cylinders needed, divide the volume of the solid block by the volume of the cylinder,
n = 360 cm³ / 180.56 cm³ = 1.99
Thus, approximately 2 cylinders are needed to mold one block of gold.
17. Area of triangle: 1/2bh
1/2 * 12 * 15
1/2 * 180
=90 cm^2
18. Area of trapezoid: 1/2 h (b1 + b2)
1/2 * 8 ( 12 + 15.4)
4 * 27.4
= 109.6 cm^2
