<span>tan(15) =
sin(15) / cos(15) =
sin(45 - 30) / cos(45 - 30) =
[ sin(45)cos(30) - sin(30)cos(45) ] / [ cos(45)cos(30) + sin(45)sin(30)]
Since sin(45) = cos(45) = √2/2, you can just factor that out from the top and bottom
[ cos(30) - sin(30) ] / [ cos(30) + sin(30)]
[ √3/2 - 1/2 ] / [ √3/2 + 1/2]
(√3 - 1) / (√3 + 1)
(√3 - 1)^2 / (√3+1)(√3 - 1)
(√3 - 1)^2 / (3 - 1)
(3 - 2√3 +1) / 2
2 - √3
There's also a formula for tan(a-b), but I couldn't remember it off hand.</span>
The length is 10
The width is 4
4 + 6 = 10
4 x 10 = 40
9514 1404 393
Answer:
168 cubic inches
Step-by-step explanation:
The formula for the volume of a pyramid is ...
V = (1/3)Bh
where B is the area of the base, and h is the height.
The base is a rectangle, whose are is given by the formula ...
A = LW
A = (8 in)(7 in) = 56 in²
Then the pyramid volume is ...
V = (1/3)(56 in²)(9 in) = 168 in³
The volume of the pyramid is 168 cubic inches.
To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. In the example above, the variable x is equal to 6 since 6 + 6 = 12. If we know the value of our variables, we can replace the variables with their values and then evaluate the expression.
