Historians are concerned with accuracy of their writings and readings but are also aware of -inability of authors to know every angle of every story -biases, perspectives, beliefs, and a variety of other differences -history being told by one person at a time -no one being totally accurate, as hard as we try

Statements reasons 1. ab ? cd; ad ? bc 1. given 2. ac ? ac 2. reflexive property 3. ? adc ? ? cba 3. ? 4. ? dac ? ? bca; ? acd ? ? cab 4. cpctc 5. ? dac and ? bca are alt. int. ? s; ? acd and ? cab are alt. int. ? s 5. definition of alternate interior angles 6. ab ? cd; ad ? bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?

The formula for the volume of a right square pyramid is given below, where a is the side length of the base and h is the height.

What are the solutions of the following system? y=-2x^2 y=x-2