Calculate Deltoid Area: Using Diagonals AC=7cm and DB=5cm

Question

Look at the deltoid ABCD below.

Given in cm:

AC = 7

DB = 5

Calculate the area of the deltoid.

777555AAABBBCCCDDD

Video Solution

Solution Steps

00:00 Calculate the area of the kite
00:03 We'll use the formula to calculate the area of a kite
00:08 (diagonal times diagonal) divided by 2
00:13 We'll substitute the appropriate values according to the given data and solve for the area
00:27 And this is the solution to the question

Step-by-Step Solution

To find the area of the deltoid ABCDABCD, we will use the area formula for a deltoid:

A=12×d1×d2 A = \frac{1}{2} \times d_1 \times d_2

where d1d_1 and d2d_2 are the lengths of the diagonals.

Given:

  • d1=AC=7cmd_1 = AC = 7 \, \text{cm}
  • d2=DB=5cmd_2 = DB = 5 \, \text{cm}

Substitute the given lengths into the formula:

A=12×7×5 A = \frac{1}{2} \times 7 \times 5

A=12×35 A = \frac{1}{2} \times 35

A=17.5cm2 A = 17.5 \, \text{cm}^2

Therefore, the area of the deltoid is 17.5cm2 17.5 \, \text{cm}^2 .

Answer

17.5 cm².