Right Triangle Area Calculation: 36cm Perimeter with Given Side Lengths

Question

Below is the right triangle ABD, which has a perimeter of 36 cm.

AB = 15

AC = 13

DC = 5

CB = 4

Work out the area of the triangle.

151515444555131313BBBCCCDDDAAA

Video Solution

Solution Steps

00:00 Calculate the area of triangle ABD
00:03 Substitute appropriate values according to the given data
00:15 The side (BD) equals the sum of its parts (BC+CD)
00:19 Substitute appropriate values according to the given data
00:24 And this is the length of the base (BD)
00:29 The perimeter of the triangle equals the sum of its sides
00:38 Substitute appropriate values
00:50 Let's solve to get DA
00:53 Let's isolate DA
01:01 Calculate and solve
01:05 And this is the height length (DA)
01:11 Now we want to calculate the area of triangle ABD
01:14 We'll use the formula for calculating triangle area
01:17 (Height(AD) multiplied by base(BD)) divided by 2
01:21 Substitute appropriate values
01:25 Calculate and solve
01:33 And this is the solution to the question

Step-by-Step Solution

According to the data:

BD=4+5=9 BD=4+5=9

Now that we are given the perimeter of triangle ABD we can find the missing side AD:

AD+15+9=36 AD+15+9=36

AD+24=36 AD+24=36

AD=3624=12 AD=36-24=12

Thus we can calculate the area of triangle ABD:

AD×BD2=12×92=1082=54 \frac{AD\times BD}{2}=\frac{12\times9}{2}=\frac{108}{2}=54

Answer

54 cm²