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.
Answer:
No. Dividing by 0 is not rational, no number works.
Answer:
3. Sides: Equilateral
Angles: Acute
4. Sides: Isosceles
Angles: Right
Step-by-step explanation:
3. Sides: Equilateral because in an equilateral triangle all sides are equal.
Angles: Acute because in an acute triangle all angles are acute.
4. Sides: Isosceles because in an isosceles triangle two legs are equal.
Angles: Right because in a right triangle, one angle is right.
Answer:
see explanation
Step-by-step explanation:
consecutive even integers have a difference of 2 between them
for example 2, 4, 6 are 3 consecutive even integers
In general if we let the first integer be k then the next 2 integers are
k + 2 and k + 4
the sum of these equals 4 times the first integer, that is 4k, hence
k + k + 2 + k + 4 = 4k
3k + 6 = 4k ( subtract 3k from both sides )
6 = k
the 3 consecutive integers are
k = 6
k + 2 = 6 + 2 = 8
k + 4 = 6 + 4 = 10
that is 6, 8 and 10
note that sum = 6 + 8 + 10 = 24
and 4 × 6 = 24
confirming the sum of the 3 integers equals 4 times the first integer
