The growth rate of the world's population is about 1.2% annually (down from 2.0% in 1972). in the year 2006 the population was about 6.6 billion. (a) determine the growth constant and doubling time which correspond to the present growth rate. (b) if the population continues to grow at 1.2% per year, what will the world's population be in 2030? (e) if the average mass of a person is 70 kg, how long would it take until the mass of people equals the mass of earth, assuming population growth of 1.2% per year? the mass of earth is 5.98 x 1024 kg.
answers 2-1. (a) 0.012 yr-1, 58 yr (b) 8.7 billion (c) 2.5x103 yr, a short time in the history of humanity

In δabc shown below, ∠bac is congruent to ∠bca: triangle abc, where angles a and c are congruent given: base ∠bac and ∠acb are congruent. prove: δabc is an isosceles triangle. when completed (fill in the blanks), the following paragraph proves that line segment ab is congruent to line segment bc making δabc an isosceles triangle. (4 points) construct a perpendicular bisector from point b to line segment ac . label the point of intersection between this perpendicular bisector and line segment ac as point d: m∠bda and m∠bdc is 90° by the definition of a perpendicular bisector. ∠bda is congruent to ∠bdc by the definition of congruent angles. line segment ad is congruent to line segment dc by by the definition of a perpendicular bisector. δbad is congruent to δbcd by the line segment ab is congruent to line segment bc because consequently, δabc is isosceles by definition of an isosceles triangle. 1. corresponding parts of congruent triangles are congruent (cpctc) 2. the definition of a perpendicular bisector 1. the definition of a perpendicular bisector 2. the definition of congruent angles 1. the definition of congruent angles 2. the definition of a perpendicular bisector 1. angle-side-angle (asa) postulate 2. corresponding parts of congruent triangles are congruent (cpctc)