Question

7) In ABC, 2B = 90°. BD is the perpendicular bisector of AC. The ratio of areas
of ADB and ABC is
A) 1:1
C) 2:1
B) 1:2
D) 1:4
​

Answer 1

Answer:

2:1

Step-by-step explanation:

• AD = CD. (perpendicular bisector divide the line in equal halves )
• angle ADB = angle CDB (given 90°)
• AD = AD (common arm)

.:. ∆ADB congruent to ∆BDC

so area of ∆ADB = area of ∆BDC = X

now area of ∆ ABC = area of ∆ADB + area of ∆BDC

= X + X = 2X

so ratio ratio of areas

of ADB and ABC is = X/ 2X = 1 : 2