Answer:
A. 69°
Explanation:
Pre-Solving
We are given that pentagon ABCDE is congruent to pentagon FGHIJ.
We want to find the measure of ∠3.
Looking at the picture, we can see that ∠3 is at the vertex labeled 'B', so another name for ∠3 is ∠B.
Recall that when naming congruent shapes, the order of the letters matters, because each letter must correspond to another letter in the other shape. In other words, the vertex A corresponds to the vertex F in the two pentagons and so on.
- The corresponding vertices means that ∠A ≅ ∠F and etc.
Solving
To start, let's look at the corresponding vertex to B.
The letter should be in the same place as where B is in ABCDE. In FGHIJ, that letter is G.
This means that vertex that corresponds to B is vertex G, which therefore means that ∠B ≅ ∠G.
We can also look to see that m∠G = 69°.
Because ∠B is congruent to this angle, the measure of ∠B is also 69°. Furthermore, since ∠B is another name for ∠3, this means that the measure of ∠3 is 69°.
So, the answer is A.