Question

What is the answer??

Answer 1

Answer:

Step-by-step explanation:

Let AC = x

AB - AC = 4 cm

AB = 4 +x  ----------------(I)

Pythagorean theorem

AB² + AC² =BC²

(4 + x)² + x² = 9²

Use the identity (a + b)² = a² + 2ab + b² where a = 4 & b = x

4² +2*4*x  +x² + x²= 81

16 + 8x + 2x² = 81

2x² + 8x + 16 - 81 = 0

2x² + 8x - 65= 0

a = 2 ; b = 8 ; c = -65

D = b² - 4ac

   = 8² - 4*2*(-65)

  = 64 +  520

D = 584

√D = √584 = 24.16

$x=\frac{-b+\sqrt{D}}{2a} \ or \ x =\frac{-b-\sqrt{D}}{2a}\\\\x= \frac{-8+24.16}{2*2} \ or \ x = \frac{-8-24.6}{2*2}$   {Ignore this as it is negative.}

x = 16.16/4

x = 4.04

AC = 4.04 Cm

AB = 4 + 4.04 = 8.04 cm

Area of triangle ABC = $\frac{1}{2}* base * height$

                                   $=\frac{1}{2}*4.04 *8.04\\\\= 2.02 * 8.04$

                                   = 16.24 sq.cm