Geometry problems (11..20) problems 1..10 problems 21..29 11. Calculate angle x. 12. In the figure below we notice right-angled triangles and their inscribed circles. Question: what is the area of the rectangle for these inscribed circle diameters? 13. In the figure below we notice right-angled triangles and their inscribed circles. Question: what is the area of the rectangle for these inscribed circle diameters? 14. find angles x, y at point D in above picture. 15. Calculate x in next picture. 16. Below is pictured rectangle ABCD with BD perpendicular to CE. Prove that BE x BA = (BC)2. 17. In picture below AD = DC LABC = 45 deg. Question: find angle x. 18. Calculate angle x. 19. Triangle ABC is isosceles and right angled. Proof that angle x = LDCE = 45 degrees. 20. Given are: A 180 degree circle arc with center P and radius c. Within two other half circles with centers M, N and radius a ,b. c = a + b. Within also two small circles with radius r which touch the other circles and line AB. AB is tangent of the inner circle arcs. Asked: Express r in a and b.