the lowest point of the dry lake bed in the example has an elevation of -18 3/4 ft what number represents the change in elevation from the start of the path to the lowest point in the dry lake bed

Can someone pls ! pls answer all. no explanation needed..

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?