PLEASE HELP!
I DONT UNDERSTAND!

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.

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.

What is the circumference of a circle with an area of 50.24 cm²?