Answer:
The length of the unknown sides of the triangles are as follows:
CD = 10√2
AC = 10√2
BC = 10
AB = 10
ΔACD is a right angle triangle. Therefore, Pythagoras theorem can be used to find the sides of the triangle.
c² = a² + b²
where
c = hypotenuse side = AD = 20
a and b are the other 2 legs
lets use trigonometric ratio to find CD,
cos 45 = adjacent / hypotenuse
cos 45 = CD / 20
CD = 1 / √2 × 20
CD = 20 / √2 = 20√2 / 2 = 10√2
20² - (10√2)² = AC²
400 - 100(2) = AC²
AC² = 200
AC = √200 = 10√2
ΔABC is a right angle triangle too. Therefore,
AB² + BC² = AC²
Using trigonometric ratio,
cos 45 = BC / 10√2
BC = 10√2 × cos 45
BC = 10√2 × 1 / √2
BC = 10√2 / √2 = 10
(10√2)² - 10² = AB²
200 - 100 = AB²
AB² = 100
AB = 10
Step-by-step explanation:
The first answer is right
(x - 9) (x + 9)
It’s me again lol
Answer: 0.31
Step-by-step explanation:
7/22 is 0.31
Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
