3. The total angle is 115, and one chunk of it is 90. Subtracting the two, gives us 25°, which should be the other measure, as m∠ABE and m∠EBC should add up to m∠ABC.
4. Same thing as before. m∠DGJ and m∠JGK should add up to m∠DGK.
Therefore, m∠DGJ is 70 - 40 = 30°.
5. When two 45° angles are put together, it will be 90°, or as it is usually called, a right angle.