circle_constraints.xml

<android.support.design.widget.FloatingActionButton
        android:id="@+id/share_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:layout_marginBottom="32dp"
        android:src="@drawable/filled"
        app:backgroundTint="#FF4E53"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <android.support.design.widget.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/icon_email"
        app:backgroundTint="#FAFAFA"
        app:layout_constraintCircle="@+id/share_icon"
        app:layout_constraintCircleAngle="0"
        app:layout_constraintCircleRadius="70dp" />

    <android.support.design.widget.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/icon_whatsapp"
        app:backgroundTint="#FAFAFA"
        app:layout_constraintCircle="@+id/share_icon"
        app:layout_constraintCircleAngle="70"
        app:layout_constraintCircleRadius="70dp" />

    <android.support.design.widget.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/icon_fb"
        app:backgroundTint="#FAFAFA"
        app:layout_constraintCircle="@+id/share_icon"
        app:layout_constraintCircleAngle="290"
        app:layout_constraintCircleRadius="70dp" />