Can someone answer this please?

The semi circle and isosceles triangle have the same base AB and the same area. Find angle x. Show workout.

Nina [5.8K]

$r= \frac{AB}{2} \\ \\A_{semi\:circle }=\frac{r^2\pi}{2} \\ \\A_{triangle}=A_{semi\:circle }=\frac{r^2\pi}{2} \\ \\A_{triangle}= \frac{2r\times h}{2} =rh \\ \\\frac{r^2\pi}{2}= rh \\ \\h=\frac{r\pi}{2} \\ \\ \tan{x}= \frac{h}{r} = \frac{\frac{r\pi}{2}}{r} =\frac{\pi}{2} \\ \\x=\arctan{\frac{\pi}{2}}
\\
\\x \approx 57.52^o$

7 0

3 years ago

The sum of first three terms of a finite geometric series is -7/10 and their product is -1/125. [Hint: Use a/r, a, and ar to rep

Alchen [17]

Ooh, fun

geometric sequences can be represented as
$a_n=a(r)^{n-1}$
so the first 3 terms are
$a_1=a$
$a_2=a(r)$
$a_2=a(r)^2$

the sum is -7/10
$\frac{-7}{10}=a+ar+ar^2$
and their product is -1/125
$\frac{-1}{125}=(a)(ar)(ar^2)=a^3r^3=(ar)^3$

from the 2nd equation we can take the cube root of both sides to get
$\frac{-1}{5}=ar$
note that a=ar/r and ar²=(ar)r
so now rewrite 1st equation as
$\frac{-7}{10}=\frac{ar}{r}+ar+(ar)r$
subsituting -1/5 for ar
$\frac{-7}{10}=\frac{\frac{-1}{5}}{r}+\frac{-1}{5}+(\frac{-1}{5})r$
which simplifies to
$\frac{-7}{10}=\frac{-1}{5r}+\frac{-1}{5}+\frac{-r}{5}$
multiply both sides by 10r
-7r=-2-2r-2r²
add (2r²+2r+2) to both sides
2r²-5r+2=0
solve using quadratic formula
for $ax^2+bx+c=0$
$x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}$
so
for 2r²-5r+2=0
a=2
b=-5
c=2

$r=\frac{-(-5) \pm \sqrt{(-5)^2-4(2)(2)}}{2(2)}$
$r=\frac{5 \pm \sqrt{25-16}}{4}$
$r=\frac{5 \pm \sqrt{9}}{4}$
$r=\frac{5 \pm 3}{4}$
so
$r=\frac{5+3}{4}=\frac{8}{4}=2$ or $r=\frac{5-3}{4}=\frac{2}{4}=\frac{1}{2}$

use them to solve for the value of a
$\frac{-1}{5}=ar$
$\frac{-1}{5r}=a$
try for r=2 and 1/2
$a=\frac{-1}{10}$ or $a=\frac{-2}{5}$

test each
for a=-1/10 and r=2
a+ar+ar²= $\frac{-1}{10}+\frac{-2}{10}+\frac{-4}{10}=\frac{-7}{10}$
it works

for a=-2/5 and r=1/2
a+ar+ar²= $\frac{-2}{5}+\frac{-1}{5}+\frac{-1}{10}=\frac{-7}{10}$
it works

both have the same terms but one is simplified

the 3 numbers are $\frac{-2}{5}$ , $\frac{-1}{5}$ , and $\frac{-1}{10}$

6 0

3 years ago

Pythagorean theorem If l = 12 cm and m = 35 cm, what is the length of n?

poizon [28]

If n is the hypotenuse, then it is 37. L can't be the hypotenuse and if m is the hypotenuse then n is 32.878

4 0

3 years ago

Read 2 more answers

The length of a rectangle is 6m more then the width. The area is 40m^2 . What is the length and the width?

erastova [34]

let the width of the rectangle be x

area of rectangle is l*b

x * (x + 6) = 40^2

x^2 + 6x = 40^2

x^2 + 6x = 1600

x + 6x =√1600

x + 6x = 40

7x = 40

x = 5.7

Hope you found this useful

4 0

4 years ago

The product is???<br><br> It is multiplication.

loris [4]

Answer:

123.76

Step-by-step explanation:

-3.4(-5.2) = 17.68

17.68(7)

123.76

Not sure if its correct but hope it helps!

7 0

3 years ago

Read 2 more answers