500,533 views
14 votes
14 votes
ABCD is a rectangle. Find angles a and b to the nearest degree

User Mika Riekkinen
by
3.3k points

1 Answer

19 votes
19 votes

Solution

Given, ABCD is a rectangle AC is diagonal

Then AD=BC and AB=CD

And ∠ABC=∠BCA=∠CDA=∠DAB=90

0

In ΔABC and ΔADC

∠ABC=∠ADC (Angle of rectangle)

AB=DC (Opposite side of rectangle )

AC=AC (Common side)

∴ΔABC≅ΔADC

∴∠ACD=∠ACB

∵∠ACD+∠ACB=90

0

..........[Angle ACB is the angle of rectangle]

∴2∠ACD=90

0

⇒∠ACD=45

0

User Ann Kilzer
by
2.8k points