A shelf is 24 inches wide. How many books, each StartFraction 7 Over 8 EndFraction of an inch thick, can fit on the shelf? Which equation can be used to solve the above problem?
24 divided by StartFraction 7 Over 8 EndFraction
StartFraction 7 Over 8 EndFraction divided by 24 = b
b divided by 24 = StartFraction 7 Over 8 EndFraction
b divided by StartFraction 7 Over 8 EndFraction = 24

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.