How to make CardView width match it height?

I have a CardView in a LinearLayout. The Layout reserves 1/5 of the screen for the CardView and 4/5 of the screen for other stuff.

I would like the cardview to be square.

I set the CardView's height to "match_parent". But how do I set it's width to match it's height?

Am I going to have to create a custom View and use OnMeasure(), or is there a simpler way?

Here is my view's XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="4" >
<!--        Other stuff goes here-->
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

        <androidx.cardview.widget.CardView
            android:id="@+id/card_view"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_margin="5dp"
            android:clickable="true"
            android:foreground="?selectableItemBackground"
            app:cardBackgroundColor="#81C784"
            app:cardCornerRadius="12dp"
            app:cardElevation="3dp"
            app:contentPadding="4dp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/card_name"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:gravity="center"
                    android:textColor="#000000"
                    android:textSize="15sp"
                    android:text="TEST"/>

                <TextView
                    android:id="@+id/card_desc"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:gravity="center"
                    android:textColor="#000000"
                    android:textSize="12sp"
                    android:text="123"/>

                <ImageView
                    android:id="@+id/card_image"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:adjustViewBounds="true"
                    android:padding="3dp"
                    android:scaleType="fitCenter"
                    android:src="@mipmap/ic_launcher"
                    />
            </LinearLayout>
        </androidx.cardview.widget.CardView>
    </LinearLayout>
</LinearLayout>

Here is a screenshot of what, roughly, I would like the cardview to look like: