Question

I need help with this.

Answer 1

12 mm

Explanation:

Use Pyth Theor

9^2 + b^2 = 15^2

81 + b^2 = 225

b^2 = 144

sqrt 144 = 12

b = 12

Answer 2

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 * 15)}= {(9 * 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 = √(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}`