Angle CAB Calculation: Analyzing Triangle Geometry with Given Data

To solve this problem, we will verify the information provided in the diagram and check if it suffices to calculate the measure of $\angle CAB$.

Firstly, consider the given data in the diagram:

• The only provided information is the measure of angle $\angle ABC = 76^\circ$.
• There are no side lengths, no additional angle measures, and no indication of the triangle being isosceles or equilateral.

Without further information, determining the measure of $\angle CAB$ is not possible:

• The sum of angles in any triangle is $180^\circ$. This requires knowing at least two angle measures to find the third.
• Only one angle measure is given, and no side lengths are known, making it impossible to calculate $\angle CAB$ directly or indirectly.

Therefore, the claim that the size of angle $\angle CAB$ can be calculated using the diagram is False.