Question

Help me pleaseI want the step by step explanation!!​

Answer 1

Answer:

The length of AB is 4.12cm and AD is 9.93cm

Step-by-step explanation:

Using the formula, a²=b²+c²-2(b)(c)cosA to find the length :

cos ∠ACB = 0.6

∠ACB = 53.1° (1d.p)

c² = 5² + 4² - 2(5)(4)cos(53.1)

= 16.98 cm

c =√16.98

= 4.12 cm

AB = 4.12 cm

∠ACD = 180° - ∠ACB

= 180° - 53.1°

= 126.9°

c² = 7² + 4² - 2(7)(4)cos(126.9)

= 98.62 cm

c = √98.62

= 9.93 cm

AD = 9.93cm

Answer 2

Answer: AB=√17, AD=√98,6

Step-by-step explanation:

AB²=BC²+AC²-2*BC*AC*cosACB

AB²=5²+4²-2*5*4*0,6=25+16-24=17

AB=√17

AD²=AC²+CD²-2*AC*CD*cosACD

cosACD=cos(180°-ACB)=-cosACB

AD²=4²+7²-2*4*7*(-0,6)=16+49+33,6=98,6

AD=√98,6