Hello, Marymack!
We know that in a geometric sequence defined by

and

, the sum can be calculated the following way:
Answer:
1 Pen cost $2.25
Step-by-step explanation:
Assume:
Cost of Pen = a
Cost of pencil = b
Cost of notebook = c
a = 3b -------------------(1)
c = 4a -------------------(2)
2a + 6b + c = $18 -----(3)
From equation (1), b = a ÷ 3 ---------(4)
Substitute equations (2) and (4) in equation (3)
2a + 6 * (a ÷ 3) + 4a = $18
2a + 2a + 4a = $18
8a = $18
a = $2.25
Therefore, 1 Pen cost $2.25
Answer:
S
Step-by-step explanation:
A=8 and PQ=28.
the way I solved the problem is attached. hope this helped.
8x + 5x + 5x = 180
18x = 180
x = 10
<span>the measure of the vertex angle = 8x = 8*10 = 80</span>°