SAT question [Proportions]

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1

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<li>In triangle ABC, AD = DB , DE is parallel to BC, and the area of triangle ABC is 40. What is the area of triangle ADE ?
A. 10
B. 15
C. 20
D. 30
E. it cannot be determined from the information given</li>
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<p>Can somebody please explain to me how they would tackle this question and questions that are similar to this one?(please no plug in methods) . I understand that its porportions but i really dont get ho to apply it since we dont know what type of triangle it is. Maybe im wrong, somebody help!</p>

2

<p>10?</p>

<p>Since you know that AB is twice AD then BC is twice DE and AC is twice AE (similar triangles). What will the height of ABC be? double.
A=1/2BH and if you double the base and height, it would be 1/4 the original. 1/4 of 40 is 10.</p>