A) The first step needs 100 bricks, the second needs 98, the third needs 96, and so on. Therefore the number of bricks for the nth step is: a_n = a_1 + d(n-1), where a_1 = 100 (the first term), d = -2 (difference).
a_n = 100 - 2(n-1) = 102 - 2n, and for the 30th step, a_30 = 102 - 2*30 = 42. So the top step will need 42 bricks.
b) The total staircase will need: 100 + 98 + 96 + ... + 44 + 42, and there are n = 30 terms. Using the formula for the sum of an arithmetic sequence:
S = (a_1 + a_n)*n/2 = (100 + 42)*30/2 = 2130
Therefore, 2130 bricks are required to build the entire staircase.
There are 180 degrees in total inside a triangle.
If something is equilateral that means that all the angles are equal.
180/3 equals 60 degrees.
That means that all angles of an equilateral triangle are always equal to each other and if you must know, are 60 degrees
Answer:
b>3.133333333
Step-by-step explanation:
13/5<b-8/15
13/5+8/15<b
39+8/15<b
47/15<b
3.13333333<b
b>3.13333333
<span>x^2 - 3x - 28 = </span><span>(x - 7)(x + 4)
answer
first one
</span><span>(x - 7)(x + 4)
</span>
hope it helps