Answer:
Option 4. Perimeter = 30 units
Step-by-step explanation:
Since the volume of a pentagonal prism is 840 cubic units.
Perpendicular distance between the bases = 14 units
We know volume of a pentagonal prism = Area of base × distance between the bases
840 = Area × 14
Area = 840/14 = 60 square units
Now area of a pentagon




Therefore perimeter of the pentagon = 5×a = 5×5.91 = 29.54 ≈ 30 units
Answer:

Step-by-step explanation:
First, let's check side lengths.
Using the Pythagorean theorem we can find the length of the other side of the rectangle.
a^2 + b^2 = c^2
4.2^2 + b^2 = 8.6^2
b^2 = 56.32
b = 7.5
The other side of the rectangle measures 7.5 cm, so now we know that 4.2 cm is indeed the shorter side of the rectangle.
For the angle in question, the 4.2 cm side is the adjacent leg.
The diagonal of 8.6 cm is the hypotenuse.
The trig ratio that relates the adjacent leg to the hypotenuse is the cosine.




For the lines to be parallel, the slope must be the same
(y2 - y1) / (x2 - x1) = slope
(7- (-3)) / (b-2) = -2
-2 (b-2) = 10
-2b + 4 = 10
-2b = 6
b = -3