Answer:
The difference between 19 and 8 is 11.
Step-by-step explanation:
Given:
The difference between a number and 8 is 11
Find the number.
Solution:
Let the unknown number be
The difference between the unknown number can be written as:
We are given that the difference =11
So we can write the equation to find as :
Using additive property to solve for
Adding 8 to both sides to isolate on one side.
∴
∴ The unknown number = 19
Given that ∠B ≅ ∠C.
to prove that the sides AB = AC
This can be done by the method of contradiction.
If possible let AB =AC
Then either AB>AC or AB<AC
Case i: If AB>AC, then by triangle axiom, Angle C > angle B.
But since angle C = angle B, we get AB cannot be greater than AC
Case ii: If AB<AC, then by triangle axiom, Angle C < angle B.
But since angle C = angle B, we get AB cannot be less than AC
Conclusion:
Since AB cannot be greater than AC nor less than AC, we have only one possibility. that is AB =AC
Hence if angle B = angle C it follows that
AB = AC, and AB ≅ AC.