Answer:
x = 8
Step-by-step explanation:
<u>Similar shapes</u> are <u>dilations</u> of each other using a <u>scale factor</u>.
As the area of both figures has been given, the scale factor that maps the green figure to the yellow figure can be calculated:

Area is measured in square units. Therefore, to find the <u>scale factor for length</u>, square root the scale factor for area:

Use the found <u>scale factor for length</u> to find the <u>perimeter</u> of the yellow figure:

Find the <u>missing horizontal lengths</u> of the yellow figure by using the corresponding length of the green figure:
⇒ 4 mm × 4 = 16 mm
⇒ 24 mm - 16 mm = 8 mm
Let the <u>height of the yellow figure</u> be y.
⇒ 24 + 8 + 16 + y + x + (y - x) = perimeter
⇒ 48 + 2y = 104
⇒ 2y = 56
⇒ y = 28 mm
Divide the yellow figure into two rectangles (see attachment).
- Area of left rectangle = y × 8 = 28 × 8 = 224 mm²
- Area of right rectangle = 16x mm²
To find x, sum the areas of the rectangles and equate to 352:
⇒ 224 + 16x = total area
⇒ 224 + 16x = 352
⇒ 16x = 128
⇒ x = 8