Undefined ReferenceError in Vuex

Am working on an SPA using Vuejs and Vuex. I'm setting some data in the store and showing it in a child component. In the child component, there are radio buttons, which when clicked, I call a function called getCalculations where I log the vehicle object but I keep getting undefined error. The child component is further embedded in parent component.

Vuex Store

const getDefaultState = () => {
    return {
        //Vehicle Data
        vehicleData: {
            reg_no: "KAS 234R",
            chasis_number: "BGSHS-IUISUS",
            engine_number: "MNVSS-8787SNS"
        }   
    }
}

const state = getDefaultState()

//getters
const getters = {
    vehicle: (state) => state.vehicleData
}

//actions
const actions = {
    //......
}

//mutations 
const mutations = {
    // .....
}

export default {
    state,
    getters,
    actions,
    mutations
}

Parent Component

<template>
<div>
  <vehicleFeature/>
</div>
</template>

<script>
import { mapGetters } from "vuex";
import vehicleFeature from "./partials/vehicleFeature";

export default {
  name: "StepFour",
  data() {
    return {
        //.....
    };
  },
  computed: mapGetters(["vehicle"]),
  components:{
    vehicleFeature
  }
</script>

Child Component

<template>
<div>
       <form class="ipf_form">
            <div class="inputGroup">
                <input id="radio4" name="radio" @change="getcalculations" type="radio" value="4">
                <label for="radio4">1 INSTALMENTS</label>
            </div>
            <div class="inputGroup">
                <input id="radio5" name="radio" @change="getcalculations" type="radio" value="5" >
                <label for="radio5">2 INSTALMENTS</label>
            </div>
       </form>
</div>
</template>


<script>
import { mapGetters } from "vuex";

export default {
  name: "vehicleFeature",
  data() {
    return {
        //.....
    };
  },
  computed: {
      ...mapGetters(["vehicle"]),
      principalamount(){
        //.....
      }
    },
  methods: {
    getcalculations() {
        console.log(this.vehicle.reg_no);
      }
  }
</script>

<style scoped>

</style>