Question

I need help with this.

Answer 1

Answer:

The length of b is 12 mm.

Step-by-step explanation:

Solution :

Here, we have given that the two sides of triangle are 9 mm and 15 mm.

Finding the third side of triangle by pythagoras theorem formula :

${\longrightarrow{\pmb{\sf{{(c)}^{2} = {(a)}^{2} + {(b)}^{2}}}}}$

• $\pink\star$ a = 9 mm
• $\pink\star$ c = 15 mm
• $\pink\star$ b = ?

Substituting all the given values in the formula to find the third side of triangle :

${\longrightarrow{\sf{{(c)}^{2} = {(a)}^{2} + {(b)}^{2}}}}$

${\longrightarrow{\sf{{(15)}^{2} = {(9)}^{2} + {(b)}^{2}}}}$

${\longrightarrow{\sf{{(15 \times 15)}= {(9 \times 9)}+ {(b)}^{2}}}}$

${\longrightarrow{\sf{{(225)}= {(81)}+ {(b)}^{2}}}}$

${\longrightarrow{\sf{225= 81+ {(b)}^{2}}}}$

${\longrightarrow{\sf{{(b)}^{2} = 225 - 81}}}$

${\longrightarrow{\sf{{(b)}^{2} = 144}}}$

${\longrightarrow{\sf{b = \sqrt{144} }}}$

${\longrightarrow{\sf{b = 12}}}$

$\star{\underline{\boxed{\sf{\purple{b = 12 \: mm}}}}}$

Hence, the length of b is 12 mm.

$\rule{300}{2.5}$

Answer 2

Answer:

12 mm

Step-by-step explanation:

Use Pyth Theor

9^2 + b^2 = 15^2

81 + b^2 = 225

b^2 = 144

sqrt 144 = 12

b = 12