From the given information, a exists jointly proportional to b and c.
then 
Therefore, the value of a exists 2.
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What is the value of a?</h3>
Given, a exists jointly proportional to b and c.

Taking K as the constant of proportionality.
a = K b c
For b = 8 and c = 9, the value of a = 4
4 = K(8)(9)
4 = 72 K
Dividing the equation by 72, we get

Using the value of K in the equation:

Substitute the values of b = 2 and c = 18, in the above equation

a = 2
Therefore, the value of a exists 2.
To learn more the value of x refers to:
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She has run 21 miles already. Let t be the number of additional miles added on.
In total, she has run t+21 miles
This is going to be set greater than 38 since "Ann will run more than 38 miles"
So we have this inequality
t+21 > 38
we solve for t by subtracting 21 from both sides
t+21 > 38
t+21-21 > 38-21
t+0 > 17
t > 17
The final answer is t > 17
which means that the possible additional number of miles she could run is anything larger than 17. So t = 18 is one possibility.
Pairs of corresponding angles have the same measure.
Answer:
9X
Step-by-step explanation: