Answer:
The expression for the nth term is Tn = 8n -7
Step-by-step explanation:
Here, we are to find an expression for the nth term of the sequence.
Mathematically, the nth term of an arithmetic sequence can be expressed as;
Tn = a + (n-1)d
for T2, the equation is
a + d = 9
for T4, the equation is
a + 3d = 25
we can substitute the equation of T2 into T4 but we first need to rewrite T4
a + d + 2d = 25
9 + 2d = 25
2d = 25 -9
2d = 16
d = 16/2
d = 8
now since a + d = 9
a = 9-d
a = 9-8
a = 1
So the expression for the nth term would be;
1 + (n-1)8
1 + 8n - 8
= 8n -8+1
= 8n -7
Let h = height of triangle
h^2 + 12^2 = 15^2
h^2 + 144 = 225
h^2 = 225 - 144
h^2 = 81
sqrt{h^2} = sqrt{81}
h = 9 cm
For part B, we need to find surface area because it represents the perimeter of this 3-D figure. The formula needed is SA = B + LA.
1. First find the lateral area.
LA = perimeter of triangle • height
LA = ph
p = 15 + 15 + 24
p = 30 + 24
p = 54 cm
LA = (54)(9)
LA = 486 cm^2
2. We now find the base of each triangle. This is found by finding the area of each triangle and multiplying by 2.
A = (1/2)bh
A = (1/2)(24)(9)
A = 108 cm^2
A = 2•108 cm^2
A = 216 cm^2 = our B in the surface area formula.
SA = B + LA
SA = 216 cm^2 + 486 cm^2
SA = 702 cm^2
The amount of cardboard needed is 702 cm^2.
Answer:
95 cents
Step-by-step explanation:
3.80/4 = 0.95
