1. The problem statement, all variables and given/known data Assuming that the sun lies at the principal focus of the solar system, and given that the semi-major axis and eccentricity of Mars is 1.5237 AU and 0.0934 respectively, calculate: The distance (in AU) when Mars is closest to the Sun (known as perihelion). The angle θ=0° 2. Relevant equations r = a(1 - e^2) / (1 +e cos θ) 3. The attempt at a solution The correct solution is 1.38 AU Though if I use the above eqn putting a=1.5237 and e=0.0934 I get an answer of 16.17. Thanks for any help!