Hello,
Answer A
Theorem of Al Kashi gives:
x²=105²+85²-2*105*85*√2/2=5628.14395...
x=75.0209... (mi)
Answer:

Step-by-step explanation:
Given
The attached circle
Required
Find the measure of x
From the attached image:
and
form a semi-circle
So:

Collect like terms


Solve for x


25 x² - 10 x = 0
5 x ( 5 x - 2 ) = 0
x = 0 and
5 x - 2 = 0
5 x = 2
x = 2: 5
x = 2/5
Answer: B ) x = 0 and x = 2/5
Given
A tea that is 22% jasmine is blended with a tea that is 13% jasmine
Find out the how many pounds of the 22% jasmine tea are used to make 10lb of tea that is 19.3% jasmine.
To proof
Let us assume that the a tea that is 22% jasmine is blended = a
Let us assume that the a tea that is 13% jasmine is blended = b
Total amount of tea made = 10lb
the equation be
a + b = 10
as given
jasmine tea are used to make 10lb of tea that is 19.3% jasmine.
write 22% in the decimal form

= 0.22
write 13% in the decimal form

= 0.13
write 19.3% in the decimal form

= 0.193
than the equation be
0.22a + 0.13b = 0.193 × 10
on simplify
22a + 13b = 193
two equation becomes
22a + 13b = 193 and a + b = 10
multiply a + b = 10 by 13 and subtracted from the 22a + 13b = 193
we get
22a - 13a + 13b -13b = 193 - 130
9a = 63
a = 7lb
put this value in the a + b = 10
we get
7 + b = 10
b = 3lb
Therefore the 22% jasmine tea are used to make 10lb of tea that is 19.3% jasmine is 7 lb .
Hence proved