Question

in fig, abcd is a quadrtialteral in which bc is 3cm ad is 13cm and dc is 12cm abd=bcd = 90degrees , find ab?????

Answer 1

Given

• ABCD is a quadrilateral
• BC = 3 cm
• AD = 13 cm
• DC = 12 cm
• ∠ABD = ∠BCD = 90°

To find

• AB

Solution

• BCD is right angled triangle at C,

By Pythagoras theorem :-

• BD² = DC² + BC²
• BD² = 12² + 3²
• BD² = 144 + 9
• BD² = 153

Similarly,

• ABD is right angled triangle at B

By Pythagoras theorem :-

• AB² = AD² - BD²
• AB² = 13² - 153
• AB² = 169 - 153
• AB = √16
• AB = 4

↦ Length of AB is 4 cm