The width is 8 because 4x8=32
What diagram is it I needa know t answer
Answer: Yes it is
Step-by-step explanation:
Answer:
394.9 cm
Step-by-step explanation:
The formula for a cone's surface area is A = π r ( r + √r^2 + h^2 ).
r = radius
h = height
The Pythagorean theorem, a^2 + b^2 = c^2, will be needed to find the height.
Plug in the values.
a(unknown)^2 + 6^2 = 15^2
A + 36 = 255
255 - 36 = 189
√189 ≈ 13.7
Surface area formula, plug in the values.
A = 3.14 × 6 ( 6 + √6^2 + 13.7^2 )
*PEMDAS*
A = 3.14 × 6 ( 6 + √36 + 187.69 )
A = 3.14 × 6 ( 6 + √223.69 )
A = 3.14 × 6 ( 6 + 14.95 )
A = 3.14 × 6 ( 20.96 )
A = 3.14 × 125.76
A = 394.8864
*round to nearest tenth*
A = 394.9 cm
Hope this helps! :)
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.
