Distribute the 3.
3*x + 3*4
3x + 12
Hope this helps :)
Answer:

Step-by-step explanation:
Let
Side of square base=x
Height of rectangular box=y
Area of square base=Area of top=
Area of one side face=
Cost of bottom=$9 per square ft
Cost of top=$5 square ft
Cost of sides=$4 per square ft
Total cost=$204
Volume of rectangular box=
Total cost=



Substitute the values of y

Differentiate w.r.t x







It takes positive because side length cannot be negative.
Again differentiate w.r. t x

Substitute the value

Hence, the volume of box is maximum at x=2.2 ft
Substitute the value of x

Greatest volume of box=
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
Step-by-step explanation:
at first solve first triangle with Pythagorean solving witch it c²=a²+b²
you have to change a bit so it will be c²-b²=a²
you start with 8 and 10 triangle and then you get line which is in the middle and yo udo just the same with triangle 8 and the solved side and you get x in the second triangle you have to use c²-a²=b²