PLEASE HELP! For a group experiment, your science class measured the fine-particulate
concentrations in the air at random places around campus, and estimated a
sample average of 22 ug/m3 (micrograms per cubic meter). If 144 readings
were taken, and the standard deviation of the sample measurements was
4 ug/m3, you are 99.7% confident that actual concentration of fine
particulates at the school is
A. 21 ug/m3 - 23 ug/m3
B. 18 pg/m3 - 26 ug/m3
C. 21.7 ug/m3 - 22.3 pg/m3
D. 21.3 ug/m3 - 22.7 ug/m3

Given: ad¯¯¯¯¯ is an altitude. prove: ab2+ac2=cb2 right triangle a b c with right angle a. point d lies on side b c and segment a d is drawn. angle a d c is a right angle. drag and drop a reason into each box to correctly complete the two-column proof. statement reason ad¯¯¯¯¯ is an altitude, and ∠bac is a right angle. given ∠adb and ∠adc are right angles. definition of altitude ∠bac≅∠bda ? ∠bac≅∠adc ? ∠b≅∠b ? ∠c≅∠c reflexive property of congruence △abc∼△dba ? △abc∼△dac aa similarity postulate abbd=cbab ? ab2=(cb)(bd) cross multiply and simplify. acdc=cbac polygon similarity postulate ac2=(cb)(dc) cross multiply and simplify. ab2+ac2=ab2+(cb)(dc) addition property of equality ab2+ac2=(cb)(bd)+(cb)(dc) substitution property of equality ab2+ac2=(cb)(bd+dc) ? bd+dc=cb segment addition postulate ab2+ac2=cb2 substitution property of equality