Here are the exact lengths of the sides of 4 triangles

triangle A: 8cm, 15cm, 17cm
triangle B: 10cm, 26cm, 24cm
triangle C: 12cm, 17cm, 21cm
triangle D: 15cm, 20cm, 25cm

which one of these triangles are not right angled?

Ateacher noticed 5/8 of the students were wearing either blue shorts or white shorts. write two different ways this could be done.

How is working backward similar to solving an equation?

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.