In ∆ABC ,D and E are points on the sides AB and AC respectively such that DE is parallel to BC , 1) If AD= 2.5 cm ,BD = 3cm ,AE = 3.75 cm find length of AC. 2) If AD = 4 cm , AE =8cm ,DB =x – 4 cm ,EC =3x -19 cm , find x 3) I f AD =2cm ,BD = 4cm , show that BC = 3 DE

1). AC=8.25cm

2). DB=7cm & EC=14cm

3). See Explanation

Step-by-step explanation:

According To the Question,

Given That, In ∆ABC, D and E are points on the sides AB and AC respectively such that DE is parallel to BC.

1). If AD= 2.5 cm ,BD = 3cm ,AE = 3.75 cm find length of AC.

Well we can apply Basic proportionality Theorem.

Since DE ║ BC ⇒ Sides are proportional and the angles are equal.

⇒ AD / BD = AE / EC

⇒ 2.5 / 3 = 3.75 / EC

On Solving we get,  

⇒ EC * 2.5 = 3.75 * 3  

⇒ EC * 2.5 = 11.25  

⇒ EC = 11.25 / 2.5  

⇒ EC = 4.5 cm

Thus,  

AC = AE + EC

⇒ AC = 3.75 + 4.50

⇒ AC = 8.25 cm  

Hence the measure of AC is 8.5 cm.

2). If AD = 4 cm , AE =8cm ,DB =x – 4 cm ,EC =3x -19 cm

Well we can apply Basic proportionality Theorem.

Since DE ║ BC ⇒ Sides are proportional and the angles are equal.

⇒ AD / BD = AE / EC

⇒ 4 / (x-4) = 8 / (3x-19)

on solving we get,

⇒ 3x-19 = 2(x-4)

⇒ 3x-19 = 2x-8

⇒x=11

Thus, DB =x–4 ⇒ 11-4 ⇒ DB=7cm

And, EC =3x-19 ⇒ 3×11-19 ⇒ EC=14cm

3). If AD=2cm , BD= 4cm , show that BC = 3 DE

Thus, AB = AD + DB = 2+4 = 6cm

Well we can apply Basic proportionality Theorem.

Since DE ║ BC ⇒ Sides are proportional and the angles are equal.

⇒ AD/AB = DE / BC

⇒ 2 / 6 = DE / BC

on solving we get

⇒ BC = 3 DE Hence, Proved

x=-2

infinite number of lines, so there is an infinite number of equations.

step-by-step explanation:

there are an infinite number of line that passes through the point (-2,5)

x=-2   is one line that passes through the point

y = 5 is another line that passes through the point

(these two lines are perpendicular to each other).

since the number of   numbers are infinite and the slope is the ratio of two numbers,(change in y over change in x) we can have an infinite number of slopes.     our only condition is that it passes through the point (-2,5)

he sells x mount because thats eqivilqant to the maz and then divided into quarters

step-by-step explanation: