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2 years ago

I need help with this pls use 3.14 with or the formula with area

Mathematics

1 answer:

Leni [432]2 years ago

6 0

Rectangle:
A=l(w)

A=12(6)

A=72cm^2

Semicircle:
r=6/2

r=3

A=(3.14(r)^2(1/2)

A=3.14(3)^2(1/2)

A=3.14(9)(1/2)

A=14.13cm^2

A=14.1cm^2

Total area: 72cm^2 + 14.1cm^2 = 86.1cm^2

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An object is thrown straight up from the top of a 100-foot platform at a velocity of 48 feet per second. The height h(t) of the

julsineya [31]

Answer:

The maximum height is 136 ft

The time it takes to achieve this height is 1.5 s.

Explanation:

1. Function for the height (given):

$h(t)=-16t^2+48t+100$

2. Type of function

That is a quadatic function, whose graph is a parabola that opens downward.

The maximum of the function, i.e. the maximum height, is the vertex of the parabola.

The vertex of a parabola with the genral equation $y=ax^2+bx+c$ is at the x-coordinate

$x=-b/(2a)$

3. Time to achieve the maximum height

Substitute b with 48 and a with - 16:

$t=-48/(2(-16))=48/32=3/2=1.5$

Then, time when the object achieves the maximum height it 1.5s

4. Maximum height:

Replace t with 1.5 in the equation, to find the maximum height, h(1.5)

$h(1.5)=-16(1.5)^2+48(1.5)+100=136$

Then, the maximum height is 136 ft

3 0

3 years ago

Tim must read 2 books from a list of 7 recommended books for his summer reading program. In how many different ways can Tim choo

Marianna [84]

There are 21 ways Tim choose 2 books from the 7 recommended book

Solution:

Given that Tim must read 2 books from a list of 7 recommended books for his summer reading program

To find: different ways can Tim choose 2 books from the 7 recommended books

This is a combination problem

A combination is a selection of all or part of a set of objects, without regard to the order in which objects are selected

The formula for combinations is:

$n C_{r}=\frac{n !}{r !(n-r) !}$

where n represents the number of items, and r represents the number of items being chosen at a time

Here we have to choose 2 books from 7 books

Therefore, n = 7 and r = 2

Substituting values in above formula, we get

$\begin{aligned}&7 C_{2}=\frac{7 !}{2 !(7-2) !}\\\\&7 C_{2}=\frac{7 !}{2 ! \times 5 !}\end{aligned}$

For a number n, the factorial of n can be written as,

$n !=n \times(n-1) \times(n-2) \dots \dots \times 2 \times 1$

Therefore, we get

$7 C_{2}=\frac{7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}{2 \times 1 \times 5 \times 4 \times 3 \times 2 \times 1}\\\\7C_2 = 7 \times 3 = 21$