{"id":11544,"date":"2022-07-18T14:40:47","date_gmt":"2022-07-18T09:10:47","guid":{"rendered":"https:\/\/mathemerize.com\/?p=11544"},"modified":"2022-07-18T14:40:52","modified_gmt":"2022-07-18T09:10:52","slug":"in-the-figure-abc-is-a-triangle-in-which-angle-abc-90-and-ad-perp-cb-produced-prove-that-ac2-ab2-bc2-2bc-bd","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/in-the-figure-abc-is-a-triangle-in-which-angle-abc-90-and-ad-perp-cb-produced-prove-that-ac2-ab2-bc2-2bc-bd\/","title":{"rendered":"In the figure, ABC is a triangle in which \\(\\angle\\) ABC > 90 and AD \\(\\perp\\) CB produced. Prove that \\({AC}^2\\) = \\({AB}^2\\) + \\({BC}^2\\) + 2BC.BD."},"content":{"rendered":"
Given<\/strong> : ABC is triangle in which \\(\\angle\\) ABC > 90 and AD \\(\\perp\\) CB produced.<\/p>\n To Prove<\/strong> : \\({AC}^2\\) = \\({AB}^2\\) + \\({BC}^2\\) + 2BC.BD<\/p>\n Proof<\/strong> : Since \\(\\triangle\\) ADB is a right triangle, angled at D. Therefore, by Pythagoras theorem,<\/p>\n \\({AB}^2\\) = \\({AD}^2\\) + \\({DB}^2\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0……..(1)<\/p>\n Again, in triangle ADC is a right triangle, angled at D.<\/p>\n Therefore, by Pythagoras theorem, we have :<\/p>\n \\({AC}^2\\) = \\({AD}^2\\) + \\({DC}^2\\)<\/p>\n \\(\\implies\\)\u00a0 \\({AC}^2\\) = \\({AD}^2\\) + \\({DB + BC}^2\\)<\/p>\n \\(\\implies\\)\u00a0 \\({AC}^2\\) = \\({AD}^2\\) + \\({DB}^2\\) + \\({BC}^2\\) + 2BC.BD<\/p>\n \\(\\implies\\)\u00a0 \\({AC}^2\\) = \\({AB}^2\\) + \\({BC}^2\\) + 2BC.BD\u00a0<\/strong> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0(by using 1)<\/p>\n","protected":false},"excerpt":{"rendered":" Solution : Given : ABC is triangle in which \\(\\angle\\) ABC > 90 and AD \\(\\perp\\) CB produced. To Prove : \\({AC}^2\\) = \\({AB}^2\\) + \\({BC}^2\\) + 2BC.BD Proof : Since \\(\\triangle\\) ADB is a right triangle, angled at D. Therefore, by Pythagoras theorem, \\({AB}^2\\) = \\({AD}^2\\) + \\({DB}^2\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0……..(1) Again, …<\/p>\n