If ab = 18, bc = 10, and ca = 13, list the angles of abc in order from smallest to largest.

∠A < ∠B < ∠C

Step-by-step explanation:

Given:  In Δ ABC

AB = 18, BC = 10, and CA = 13

We can see that

10<13<18

Thus, BC < CA < AB   (1)

We know that in triangles the larger angle to opposite to the largest side if larger.

Since, ∠A is opposite to BC

∠B is opposite to CA

∠C is opposite to AB

Therefore, from (1), we have

∠A < ∠B < ∠C

Thus, the angles of ΔABC in order from smallest to largest will be

∠A < ∠B < ∠C