document.write( "Question 1210491: In triangle ABC, the orthocenter H lies on altitude \overline{AD}. Find \frac{AH}{HD}. \n" ); document.write( "
Algebra.Com's Answer #852899 by CPhill(2138) You can put this solution on YOUR website! The ratio $\frac{AH}{HD}$ is $\mathbf{2}$.\r \n" ); document.write( "\n" ); document.write( "Here is the reasoning based on the properties of an equilateral triangle:\r \n" ); document.write( "\n" ); document.write( "## Orthocenter and Centroid in an Equilateral Triangle\r \n" ); document.write( "\n" ); document.write( "In any triangle, the **orthocenter** ($H$) is the intersection point of the altitudes. The **centroid** ($G$) is the intersection point of the medians.\r \n" ); document.write( "\n" ); document.write( "1. **Coincident Centers:** In an **equilateral triangle** ($\triangle ABC$): \n" ); document.write( " * The median from any vertex is also the altitude from that vertex. \n" ); document.write( " * This means the orthocenter ($H$), the centroid ($G$), the circumcenter, and the incenter all coincide at the same point. \n" ); document.write( " * Therefore, the orthocenter $H$ is the same point as the centroid $G$.\r \n" ); document.write( "\n" ); document.write( "2. **Median Property:** $\overline{AD}$ is an altitude (given) and, because the triangle is equilateral, it is also a median. The centroid ($G$ or $H$) divides any median into two segments in a ratio of $\mathbf{2:1}$. \r \n" ); document.write( "\n" ); document.write( "[Image of a triangle and its medial triangle with area ratio labeled]\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3. **Ratio Calculation:** The segment connecting the vertex ($A$) to the centroid ($H$) is twice as long as the segment connecting the centroid ($H$) to the midpoint ($D$) of the opposite side ($\overline{BC}$).\r \n" ); document.write( "\n" ); document.write( "$$AH = 2 \cdot HD$$\r \n" ); document.write( "\n" ); document.write( "Therefore, the ratio is: \n" ); document.write( "$$\frac{AH}{HD} = \mathbf{2}$$ \n" ); document.write( " |