Answer:
Option B is correct.
Angle DAC is congruent to angle DAB
Step-by-step explanation:
Given: Segment AC is congruent to segment AB.
In ΔABD and ΔACD
[Given]
[Congruent sides have the same length]
AB = AC [Side]
AD = AD [Common side]
[Angle]
Side Angle Side(SAS) Postulate states that if two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the two triangles are congruent.
Then by SAS,

By CPCT [Corresponding Parts of congruent Triangles are congruent]
then;

therefore, only statement which is used to prove that angle ABD is congruent to angle ACD is: Angle DAC is congruent to DAB
Okay, so there's a number rounded to the nearest million, in this case 2 million. So this tells me that the number of visitors is between 1,500,000 and 2,499,999. The reason why 1,499,999 doesn't count is because the hundred thousands digit is not 5 or above, so it doesn't count. It would round down to 1 million, not 2 million. The reason why 2,500,000 doesn't count, is because the hundred thousands digit is 5, so that rounds to 3 million, not 2 million. The greatest number of visitors that visited the aquarium has to be 2,499,999, because that's one digit away from 2.5 million, and the hundred thousands digit is a 4, not 5. The answer is 2,499,999
Yes 1.999 is an <span>irrational number</span>